A007054 -id:A007054 - cp's OEIS frontend

A005700 a(n) = C(n)*C(n+2) - C(n+1)^2 where C() are the Catalan numbers A000108.

1, 1, 3, 14, 84, 594, 4719, 40898, 379236, 3711916, 37975756, 403127256, 4415203280, 49671036900, 571947380775, 6721316278650, 80419959684900, 977737404590100, 12058761323277900, 150656212896017400, 1904342169333848400, 24328661192286773400, 313839729380499376860

Offset: 0

N. J. A. Sloane

The old name was: Number of closed walks of 2n unit steps north, east, south, or west starting and ending at the origin and confined to the first octant.
Image of Catalan numbers (A000108) under "little Hankel" transform that sends [c_0, c_1, ...] to [d_0, d_1, ...] where d_n = c_n^2 - c_{n+1}*c_{n-1}.
The Niederhausen reference counts various classes of first octant paths by number of contacts with the line y=x. - David Callan, Sep 18 2007
In Sloane and Plouffe (1995) this was incorrectly described as "Dyck paths".
Also matchings avoiding a certain pattern (see J. Bloom and S. Elizalde). - N. J. A. Sloane, Jan 02 2013
From Bruce Westbury, Aug 22 2013: (Start)
a(n) is also the number of nested pairs of Dyck paths of length n starting and ending at the origin;
a(n) is also the number of 3-noncrossing perfect matchings on 2n points;
a(n) is also the number of 2-triangulations on n-gon;
a(n) is also the dimension of the invariant subspace of 2n-th tensor power of the spin representation of Spin(5);
a(n) is also the dimension of the invariant subspace of 2n-th tensor power of the defining representation of Sp(4). (End)
a(-1) = -3/2, a(-2) = -1/4 makes some formulas true for all n in Z. - Michael Somos, Oct 02 2014
a(n) is the number of uniquely sorted permutations of length 2n+1 that avoid the pattern 312. - Colin Defant, Jun 08 2019

			Example: a(2)=3 counts EWEW, EEWW, ENSW.
G.f. = 1 + x + 3*x^2 + 14*x^3 + 84*x^4 + 594*x^5 + 4719*x^6 + 40898*x^7 + ...

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Vincenzo Librandi, Table of n, a(n) for n = 0..200
Andrei Asinowski, Cyril Banderier, and Sarah J. Selkirk, From Kreweras to Gessel: A walk through patterns in the quarter plane, Séminaire Lotharingien de Combinatoire, Proc. 35th Conf. Formal Power Series and Alg. Comb. (Davis, 2023) Vol. 89B, Art. #30.
Jonathan Bloom and Sergi Elizalde, Pattern avoidance in matchings and partitions, arXiv preprint arXiv:1211.3442 [math.CO], 2012. See Table 1.
N. Bonichon, A bijection between realizers of maximal plane graphs and pairs of non-crossing Dyck paths, Discr. Math., 298 (2005), 104-114.
Matteo Cervetti and Luca Ferrari, Pattern avoidance in the matching pattern poset, arXiv:2009.01024 [math.CO], 2020. See Section 2.
W. Y. C. Cheng, E. Y. P. Deng, R. R. X. Du, R. P. Stanley and C. H. Yan, Crossings and nestings of matchings and partitions, arXiv:math/0501230 [math.CO], 2005.
S. J. Cyvin and I. Gutman, Kekulé structures in benzenoid hydrocarbons, Lecture Notes in Chemistry, No. 46, Springer, New York, 1988 (see p. 183).
C. P. Davis-Stober, A bijection between a set of lexicographic semiorders and pairs of non-crossing Dyck paths, Journal of Mathematical Psychology, 54, 471-474.
Myriam de Sainte-Catherine, Couplages et Pfaffiens en Combinatoire, Physique et Informatique, PhD Dissertation, Université Bordeaux I, 1983. (Annotated scanned copy of pages III.42-III.45)
Colin Defant, Catalan Intervals and Uniquely Sorted Permutations, arXiv:1904.02627 [math.CO], 2019.
Stefan Felsner, Eric Fusy, Marc Noy, and David Orden, Bijections for Baxter families and related objects, J. Combin. Theory Ser. A, 118(3):993-1020, 2011. See Theorem 8.4.
E. Fusy, D. Poulalhon, and G. Schaeffer, Bijective counting of plane bipolar orientations and Schnyder words, Eur. J. Combinat. 30 (2009) 1646-1658, eq (2).
Juan B. Gil, Peter R. W. McNamara, Jordan O. Tirrell, and Michael D. Weiner, From Dyck paths to standard Young tableaux, arXiv:1708.00513 [math.CO], 2017.
D. Gouyou-Beauchamps, Chemins sous-diagonaux et tableaux de Young, pp. 112-125 of "Combinatoire Enumerative (Montreal 1985)", Lect. Notes Math. 1234, Springer 1986.
D. Gouyou-Beauchamps, Chemins sous-diagonaux et tableaux de Young, pp. 112-125 of "Combinatoire Enumerative (Montreal 1985)", Lect. Notes Math. 1234, Springer, 1986. (Annotated scanned copy)
D. Gouyou-Beauchamps. Standard Young tableaux of height 4 and 5, European J. Combin. 10 (1989) 69 - 82.
Nicholas M. Katz, A Note on Random Matrix Integrals, Moment Identities, and Catalan Numbers, preprint, 2015; Mathemtika, Volume 62, Issue 3 2016 , pp. 811-817.
Kiran S. Kedlaya and Andrew V. Sutherland, Hyperelliptic curves, L-polynomials and random matrices, arXiv:0803.4462 [math.NT], 2008-2010.
Alec Mihailovs, Enumeration of walks on lattices, arXiv:math/9803128 (1998).
Heinrich Niederhausen, A Note on the Enumeration of Diffusion Walks in the First Octant by Their Number of Contacts with the Diagonal, Journal of Integer Sequences, Vol. 8 (2005), Article 05.4.3.
Maya Sankar, Further Bijections to Pattern-Avoiding Valid Hook Configurations, arXiv:1910.08895 [math.CO], 2019.
Robert Scherer, Topics in Number Theory and Combinatorics, Ph. D. Dissertation, Univ. of California Davis (2021).
Index entries for sequences related to Young tableaux.

A column of the triangle in A179898. A diagonal of the triangle in A185249.
Row sums of A193691, A193692. - Alois P. Heinz, Aug 03 2011
See A138349 for another version.
Cf. A000108, A006149, A006150, A248152.

LiE
```
p_tensor(2*n,[0,1],B2)|[0,0]
```
LiE
```
p_tensor(2*n,[1,0],C2)|[0,0]
```

[6*Factorial(2*n)*Factorial(2*n+2)/(Factorial(n)*Factorial(n+1)* Factorial(n+2)*Factorial(n+3)): n in [0..25]]; // Vincenzo Librandi, Aug 04 2011

CoefficientList[ Series[ HypergeometricPFQ[ {1, 1/2, 3/2}, {3, 4}, 16 x], {x, 0, 19}], x]
a[ n_] := If[ n < 1, Boole[n == 0], Det[ Table[ Binomial[i + 1, j - i + 2], {i, n}, {j, n}]]]; (* Michael Somos, Feb 25 2014 *) (* slight modification of David Callan formula *)
a[ n_] := 12 * 4^n * (2*n-1)!! * (2*n+1)!! / ((n+2)! * (n+3)!); (* Michael Somos, Oct 02 2014 *)

a(n)=6*binomial(2*n+2,n)*(2*n)!/(n+1)!/(n+3)! \\ Charles R Greathouse IV, Aug 04 2011

{a(n) = if( n<0, if( n<-2, 0, [-3/2, -1/4][-n]), 6 * (2*n)! * (2*n+2)! / (n! * (n+1)! * (n+2)! * (n+3)!))}; /* Michael Somos, Oct 02 2014 */

G.f.: 3F2( [ 1, 1/2, 3/2 ]; [ 3, 4 ]; 16 x ).
a(n) = 6*(2*n)!*(2*n+2)!/(n!*(n+1)!*(n+2)!*(n+3)!) (Mihailovs).
a(n) = Det[Table[binomial[i+1, j-i+2], {i, 1, n}, {j, 1, n}]]. - David Callan, Jul 20 2005
a(n) = b(n)b(n+1)/6 where b(n) is the superballot number A007054. - David Callan, Feb 01 2007
a(n) = A000108(n)*A000108(n+2) - A000108(n+1)^2. - Philippe Deléham, Apr 11 2007
G.f.: (1 + 6*x - hypergeom([-1/2,-3/2],[2],16*x))/(4*x^2). - Mark van Hoeij, Nov 02 2009
From Michael Somos, Oct 02 2014: (Start)
a(n) = 12 * 4^n * (2*n-1)!! * (2*n+1)!! / ((n+2)! * (n+3)!).
D-finite with recurrence 0 = a(n) * 4*(2*n+1)*(2*n+3) - a(n+1) * (n+3)*(n+4) for all n in Z.
0 = a(n)*(+65536*a(n+2) - 72192*a(n+3) + 10296*a(n+4)) + a(n+1)*(-1536*a(n+2) - 1632*a(n+3) - 282*a(n+4)) + a(n+2)*(+40*a(n+2) - 6*a(n+3) + a(n+4)) for all n in Z.
0 = a(n)^2*a(n+2)*(+1792*a(n+1) - 882*a(n+2)) + a(n)*a(n+1)^2*(+768*a(n+1) + 580*a(n+2)) + 7*a(n)*a(n+1)*a(n+2)^2 +a(n+1)^3*(-18*a(n+1) + 3*a(n+2)) for all n in Z. (End)
a(n) ~ 3 * 2^(4*n+3) / (Pi * n^5). - Vaclav Kotesovec, Feb 10 2015
From Peter Bala, Feb 22 2023: (Start)
a(n) = (12*(2*n - 1)/((n + 1)(n + 2)(n + 3))) * Catalan(n-1)*Catalan(n+1) for n >= 1.
a(n) = Product_{1 <= i <= j <= n-1} (i + j + 4)/(i + j).
a(n) = (1/2^(n-1)) * Product_{1 <= i <= j <= n-1} (i + j + 4)/(i + j - 1) for n >= 1. (End)
Sum_{n>=0} a(n)/16^n = 88 - 4096/(15*Pi). - Amiram Eldar, May 06 2023

More terms from James Sellers, Dec 24 1999
Corrected by Vladeta Jovovic, May 23 2004
Better definition from David Callan, Sep 18 2007
Definition simplified by N. J. A. Sloane, Nov 30 2020

A000257 Number of rooted bicubic maps: a(n) = (8n-4)a(n-1)/(n+2) for n >= 2, a(0) = a(1) = 1.

Original entry on oeis.org

1, 1, 3, 12, 56, 288, 1584, 9152, 54912, 339456, 2149888, 13891584, 91287552, 608583680, 4107939840, 28030648320, 193100021760, 1341536993280, 9390758952960, 66182491668480, 469294031831040, 3346270487838720, 23981605162844160, 172667557172477952

Offset: 0

N. J. A. Sloane

Number of rooted Eulerian planar maps with n edges. - Valery A. Liskovets, Apr 07 2002
Number of indecomposable 1342-avoiding permutations of length n.
Also counts rooted planar 2-constellations with n digons. - Valery A. Liskovets, Dec 01 2003
a(n) is also the number of rooted planar hypermaps with n darts (darts are semi-edges in the particular case of ordinary maps). - Valery A. Liskovets, Apr 13 2006
Number of "new" intervals in Tamari lattices of size n (see Chapoton paper). - Ralf Stephan, May 08 2007

			G.f. = 1 + x + 3*x^2 + 12*x^3 + 56*x^4 + 288*x^5 + 1584*x^6 + 9152*x^7 + ...

Miklos Bona, editor, Handbook of Enumerative Combinatorics, CRC Press, 2015, page 321.
L. M. Koganov, V. A. Liskovets, T. R. S. Walsh, Total vertex enumeration in rooted planar maps, Ars Combin., Vol. 54 (2000), pp. 149-160.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

T. D. Noe, Table of n, a(n) for n = 0..200
Edward A. Bender and E. Rodney Canfield, The number of degree restricted maps on the sphere, SIAM J. Discr. Math., Vol. 7, No. 1 (1994), pp. 9-15.
Daniel Birmajer, Juan B. Gil, and Michael D. Weiner, A family of Bell transformations, arXiv:1803.07727 [math.CO], 2018.
Jonathan Bloom and Vince Vatter, Two Vignettes On Full Rook Placements, arXiv preprint arXiv:1310.6073 [math.CO], 2013.
Miklós Bóna, Exact enumeration of 1342-avoiding permutations: A close link with labeled trees and planar maps, arXiv:math/9702223 [math.CO], 1997.
Nicolas Bonichon, Mireille Bousquet-Mélou, Paul Dorbec, and Claire Pennarun, On the number of planar Eulerian orientations, arXiv:1610.09837 [math.CO], 2016.
Nicolas Bonichon, Mireille Bousquet-Mélou, and Éric Fusy, Baxter permutations and plane bipolar orientations Sem. Lothar. Combin. 61A (2009/10), Art. B61Ah, 29 pp. See Section 8. - _N. J. A. Sloane_, Mar 27 2014
Valentin Bonzom, Guillaume Chapuy, and Maciej Dolega, Enumeration of non-oriented maps via integrability, Alg. Combin. 5 (6) (2022) pp. 1363-1390, A.2.
Alin Bostan, Frédéric Chyzak, and Vincent Pilaud, Refined product formulas for Tamari intervals, arXiv:2303.10986 [math.CO], 2023.
Mireille Bousquet-Mélou, Limit laws for embedded trees, arXiv:math/0501266 [math.CO], 2005.
Mireille Bousquet-Mélou and G. Schaeffer, Enumeration of planar constellations, Adv. in Appl. Math., Vol. 24, No. 4 (2000), pp. 337-368.
Frédéric Chapoton, Sur le nombre d'intervalles dans les treillis de Tamari, arXiv:math/0602368 [math.CO], 2006.
P. Di Francesco, O. Golinelli and E. Guitter, Meanders and the Temperley-Lieb algebra, arXiv:hep-th/9602025, 1996; see Eq. C.1.
Wenjie Fang, Bijective link between Chapoton's new intervals and bipartite planar maps, arXiv:2001.04723 [math.CO], 2020.
Alice L.L. Gao, Sergey Kitaev, and Philip B. Zhang, On pattern avoiding indecomposable permutations, arXiv:1605.05490 [math.CO], 2016.
Juan B. Gil, David Kenepp, and Michael Weiner, Pattern-avoiding permutations by inactive sites, Pennsylvania State University, Altoona (2020).
Hsien-Kuei Hwang, Mihyun Kang, and Guan-Huei Duh, Asymptotic Expansions for Sub-Critical Lagrangean Forms, LIPIcs Proceedings of Analysis of Algorithms 2018, Vol. 110, Schloss Dagstuhl-Leibniz-Zentrum für Informatik, 2018.
Christian Kassel and Christophe Reutenauer, Algebraicity of the zeta function associated to a matrix over a free group algebra, arXiv:1303.3481 [math.CO], 2013-2014.
Philippe Leroux, A simple symmetry generating operads related to rooted planar m-ary trees and polygonal numbers, arXiv:math/0512437 [math.CO], 2005.
Zhaoxiang Li and Yanpei Liu, Chromatic sums of general maps on the sphere and the projective plane, Discr. Math., Vol. 307, No. 1 (2007), pp. 78-87.
Valery A. Liskovets and Timothy R. S. Walsh, Enumeration of Eulerian and unicursal planar maps, Discr. Math., Vol. 282, No. 1-3 (2004), pp. 209-221.
Alexander Mednykh and Roman Nedela, Counting unrooted hypermaps on closed orientable surface, 18th Intern. Conf. Formal Power Series & Algebr. Comb., Jun 19, 2006, San Diego, California (USA).
Alexander Mednykh and Roman Nedela, Enumeration of unrooted hypermaps of a given genus, Discr. Math., Vol. 310, No. 3 (2010), pp. 518-526. [From _N. J. A. Sloane_, Dec 19 2009]
Mednykh, A.; Nedela, R. Recent progress in enumeration of hypermaps, J. Math. Sci., New York 226, No. 5, 635-654 (2017) and Zap. Nauchn. Semin. POMI 446, 139-164 (2016). Table 2
Wojciech Mlotkowski and Karol A. Penson, A Fuss-type family of positive definite sequences, arXiv:1507.07312 [math.PR], 2015.
Simon Plouffe, Approximations de séries génératrices et quelques conjectures, Dissertation, Université du Québec à Montréal, 1992, arXiv:0911.4975 [math.NT], 2009.
Simon Plouffe, Une méthode pour obtenir la fonction génératrice d'une série., arXiv:0912.0072 [math.NT], 2009; FPSAC 1993, Florence. Formal Power Series and Algebraic Combinatorics.
W. T. Tutte, A Census of Planar Maps, Canad. J. Math., Vol. 15 (1963), pp. 249-271.
T. R. S. Walsh, Hypermaps versus bipartite maps, J. Combin. Th., Series B, Vol. 18, No. 2 (1975), pp. 155-163.
Timothy R. Walsh, Space-efficient generation of nonisomorphic maps and hypermaps.
T. R. Walsh, Space-Efficient Generation of Nonisomorphic Maps and Hypermaps, J. Int. Seq., Vol. 18 (2015), Article 15.4.3.
Peter G. Zograf, Enumeration of Grothendieck's Dessins and KP Hierarchy, International Mathematics Research Notices, Volume 2015, Issue 24 (1 January 2015), pp. 13533-13544.

Cf. A069726, A007054, A298358 (rooted).

First row of array A101477.

[1] cat [3*2^n*Factorial(2*n)/((2*n^2+6*n+4)*Factorial(n)^2): n in [1.. 25]]; // Vincenzo Librandi, Oct 21 2014

A000257 := proc(n)
        option remember;
        if n <=1 then
                1;
        else
                4*(2*n-1)*procname(n-1)/(n+2) ;
        end if ;
end proc: # R. J. Mathar, Dec 18 2011

CoefficientList[Series[1 + x HypergeometricPFQ[{1, 3/2}, {4}, 8 x], {x, 0, 10}], x]
(* Second program: *)
Join[{1}, Table[3*2^(n-1) CatalanNumber[n]/(n+2), {n, 30}]] (* Harvey P. Dale, Dec 18 2011 *)

C(n)=binomial(2*n, n)/(n+1);
a(n)=if(n==0, 1, 3*2^(n-1)*C(n)/(n+2) ); \\ Joerg Arndt, May 04 2013

x='x+O('x^66); Vec( ((1-8*x)^(3/2) + 8*x^2 + 12*x - 1)/(32*x^2) ) \\ Joerg Arndt, May 04 2013

x='x; y='y; Fxy = 16*x^2*y^2 - (8*x^2+12*x-1)*y + x^2+11*x-1;
seq(N) = {
  my(y0 = 1 + O('x^N), y1=0);
  for (k = 1, N,
    y1 = y0 - subst(Fxy, y, y0)/subst(deriv(Fxy, y), y, y0);
    if (y1 == y0, break()); y0 = y1);
  Vec(y0);
};
seq(24) \\ Gheorghe Coserea, Nov 30 2016

a000257 = [1]
for n in range(1, 25): a000257.append((8*n-4)*a000257[-1]//(n+2))
print(a000257) # Gennady Eremin, Mar 22 2022

a(0) = 1 and a(n) = 3*2^(n-1)*C(n)/(n+2) for n >= 1, where C = Catalan (A000108).
a(n) = 2^(n-2) * A007054(n), n > 1.
O.g.f.: 1/4 + (1/8) * ( -(1-8*x)^(1/2) + 16*(1-8*x)^(1/2)*x+1-8*x ) / ((1-8*x)^(1/2)*x*(1+(1-8*x)^(1/2))). - Karol A. Penson, Jun 04 2004
E.g.f.: (1/8) * exp(4*x)*(8*BesselI(0, 4*x)*x-BesselI(1, 4*x)-8*BesselI(1, 4*x)*x)/x. - Karol A. Penson, Jun 04 2004
O.g.f.: 1 + x*2F1( (1, 3/2); (4); 8*x). - Olivier Gérard, Feb 15 2011
D-finite with recurrence (n + 2) * a(n) = (8*n - 4) * a(n - 1). - Simon Plouffe, Feb 09 2012
O.g.f.: ((1-8*x)^(3/2) + 8*x^2 + 12*x - 1)/(32*x^2) = 1 + x + 3*x^2 + 12*x^3 + 56*x^4 + .... The related generating function 1 + 3*x^2 + 12*x^4 + 56*x^6 + ... is the zeta function associated to a certain 2 X 2 matrix of noncommuting variables. See Kassel and Reutenauer, Example 5.1. - Peter Bala, Mar 15 2013
a(n) ~ 3*2^(3*n-1) / (sqrt(Pi)*n^(5/2)). - Vaclav Kotesovec, Mar 10 2014
0 = a(n) * (64*a(n+1) - 28*a(n+2)) + a(n+1) * (12*a(n+1) + a(n+2)) if n > 0. - Michael Somos, Apr 03 2014
Integral representation as the n-th moment of the positive function W(x) on (0,8). a(n) = Integral_{x=0..8} x^n*W(x) dx, n=1,2,3,..., where W(x) = sqrt((8-x)^3/x)/(32*Pi). For n=0 the integral is equal to 3/4. This means that a(n) is the n-th moment, n=0,1,2,..., of the probability distribution which is a sum of W(x) as the continuous part and an atom at x=0 with weight 1/4 (Dirac(x)/4). This representation is unique as W(x) is the solution of the Hausdorff moment problem. - Karol A. Penson and Wojciech Mlotkowski, Jul 15 2015
G.f. y satisfies: 0 = 16*x^2*y^2 - (8*x^2+12*x-1)*y + x^2+11*x-1. - Gheorghe Coserea, Nov 22 2016
A(x) = (1 + 4*y - y^2)/4, where y = C(2*x), C being the g.f. for A000108. - Gheorghe Coserea, Apr 10 2018
From Amiram Eldar, Mar 22 2022: (Start)
Sum_{n>=0} 1/a(n) = 1985/1029 + 1280*arcsin(1/(2*sqrt(2)))/(343*sqrt(7)).
Sum_{n>=0} (-1)^n/a(n) = 341/729 - 1280*arcsinh(1/(2*sqrt(2)))/2187. (End)
O.g.f.: x*A(x) is the compositional inverse of x - x^2*B(x), where B(x) is the o.g.f. of A165546. - Alexander Burstein, Aug 02 2024

A002421 Expansion of (1-4*x)^(3/2) in powers of x.

Original entry on oeis.org

1, -6, 6, 4, 6, 12, 28, 72, 198, 572, 1716, 5304, 16796, 54264, 178296, 594320, 2005830, 6843420, 23571780, 81880920, 286583220, 1009864680, 3580429320, 12765008880, 45741281820, 164668614552, 595340375688, 2160865067312, 7871722745208, 28772503827312

Offset: 0

N. J. A. Sloane

Terms that are not divisible by 12 have indices in A019469. - Ralf Stephan, Aug 26 2004
From Ralf Steiner, Apr 06 2017: (Start)
By analytic continuation to the entire complex plane there exist regularized values for divergent sums such as:
Sum_{k>=0} a(k)^2/8^k = 2F1(-3/2,-3/2,1,2).
Sum_{k>=0} a(k) / 2^k = -i. (End)

			G.f. = 1 - 6*x + 6*x^2 + 4*x^3 + 6*x^4 + 12*x^5 + 28*x^6 + 72*x^7 + 198*x^8 + 572*x^9 + ...

A. Fletcher, J. C. P. Miller, L. Rosenhead and L. J. Comrie, An Index of Mathematical Tables. Vols. 1 and 2, 2nd ed., Blackwell, Oxford and Addison-Wesley, Reading, MA, 1962, Vol. 1, p. 55.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
T. N. Thiele, Interpolationsrechnung. Teubner, Leipzig, 1909, p. 164.

Vincenzo Librandi, Table of n, a(n) for n = 0..1000
N. J. A. Sloane, Notes on A984 and A2420-A2424

Cf. A007054, A004001, A002420, A002422, A002423, A002424.

Cf. A000257, A001622, A071721, A071724, A085687.

Concatenation([1], List([1..40], n-> 12*Factorial(2*n-4) /( Factorial(n)*Factorial(n-2)) )) # G. C. Greubel, Jul 03 2019

[1,-6] cat [12*Catalan(n-2)/n: n in [2..30]]; // Vincenzo Librandi, Jun 11 2012

A002421 := n -> 3*4^(n-1)*GAMMA(-3/2+n)/(sqrt(Pi)*GAMMA(1+n)):
seq(A002421(n), n=0..29); # Peter Luschny, Dec 14 2015

CoefficientList[Series[(1-4x)^(3/2),{x,0,40}],x] (* Vincenzo Librandi, Jun 11 2012 *)
a[n_]:= Binomial[ 3/2, n] (-4)^n; (* Michael Somos, Dec 04 2013 *)
a[n_]:= SeriesCoefficient[(1-4x)^(3/2), {x, 0, n}]; (* Michael Somos, Dec 04 2013 *)

{a(n) = binomial( 3/2, n) * (-4)^n}; /* Michael Somos, Dec 04 2013 */

{a(n) = if( n<0, 0, polcoeff( (1 - 4*x + x * O(x^n))^(3/2), n))}; /* Michael Somos, Dec 04 2013 */

((1-4*x)^(3/2)).series(x, 40).coefficients(x, sparse=False) # G. C. Greubel, Jul 03 2019

a(n) = Sum_{m=0..n} binomial(n, m)*K_m(4), where K_m(x) = K_m(n, 2, x) is a Krawtchouk polynomial. - Alexander Barg (abarg(AT)research.bell-labs.com)
a(n) ~ (3/4)*Pi^(-1/2)*n^(-5/2)*2^(2*n)*(1 + 15/8*n^-1 + ...). - Joe Keane (jgk(AT)jgk.org), Nov 22 2001
From Ralf Stephan, Mar 11 2004: (Start)
a(n) = 12*(2*n-4)! /(n!*(n-2)!), n > 1.
a(n) = 12*Cat(n-2)/n = 2(Cat(n-1) - 4*Cat(n-2)), in terms of Catalan numbers (A000108).
Terms that are not divisible by 12 have indices in A019469. (End)
Let rho(x)=(1/Pi)*(x*(4-x))^(3/2), then for n >= 4, a(n) = Integral_{x=0..4} (x^(n-4) *rho(x)) dx. - Groux Roland, Mar 16 2011
G.f.: (1-4*x)^(3/2) = 1 - 6*x + 12*x^2/(G(0) + 2*x); G(k) = (4*x+1)*k-2*x+2-2*x*(k+2)*(2*k+1)/G(k+1); for -1/4 <= x < 1/4, otherwise G(0) = 2*x; (continued fraction). - Sergei N. Gladkovskii, Dec 05 2011
G.f.: 1/G(0) where G(k) = 1 + 4*x*(2*k+1)/(1 - 1/(1 + (2*k+2)/G(k+1))); (continued fraction, 3-step). - Sergei N. Gladkovskii, Nov 18 2012
G.f.: G(0)/2, where G(k) = 2 + 2*x*(2*k-3)*G(k+1)/(k+1). - Sergei N. Gladkovskii, Jun 06 2013 [Edited by Michael Somos, Dec 04 2013]
0 = a(n+2) * (a(n+1) - 14*a(n)) + a(n+1) * (6*a(n+1) + 16*a(n)) for all n in Z. - Michael Somos, Dec 04 2013
A232546(n) = 3^n * a(n). - Michael Somos, Dec 04 2013
G.f.: hypergeometric1F0(-3/2;;4*x). - R. J. Mathar, Aug 09 2015
a(n) = 3*4^(n-1)*Gamma(-3/2+n)/(sqrt(Pi)*Gamma(1+n)). - Peter Luschny, Dec 14 2015
From Ralf Steiner, Apr 06 2017: (Start)
Sum_{k>=0} a(k)/4^k = 0.
Sum_{k>=0} a(k)^2/16^k = 32/(3*Pi).
Sum_{k>=0} a(k)^2*(k/8)/16^k = 1/Pi.
Sum_{k>=0} a(k)^2*(-k/24+1/8)/16^k = 1/Pi.
Sum_{k>=0} a(k-1)^2*(k-1/4)/16^k = 1/Pi.
Sum_{k>=0} a(k-1)^2*(2k-2)/16^k = 1/Pi.(End)
D-finite with recurrence: n*a(n) +2*(-2*n+5)*a(n-1)=0. - R. J. Mathar, Feb 20 2020
From Amiram Eldar, Mar 22 2022: (Start)
Sum_{n>=0} 1/a(n) = 4/3 + 10*Pi/(81*sqrt(3)).
Sum_{n>=0} (-1)^n/a(n) = 92/75 - 4*sqrt(5)*log(phi)/125, where phi is the golden ratio (A001622). (End)

A007272 Super ballot numbers: 60(2n)!/(n!(n+3)!).

Original entry on oeis.org

10, 5, 6, 10, 20, 45, 110, 286, 780, 2210, 6460, 19380, 59432, 185725, 589950, 1900950, 6203100, 20470230, 68234100, 229514700, 778354200, 2659376850, 9148256364, 31667041260, 110248217720, 385868762020, 1357193576760, 4795417304552, 17015996887120, 60619488910365

Offset: 0

N. J. A. Sloane, Simon Plouffe, Ira M. Gessel

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Matthew House, Table of n, a(n) for n = 0..1677
Emily Allen and Irina Gheorghiciuc, A Weighted Interpretation for the Super Catalan Numbers, J. Int. Seq. 17 (2014) # 14.10.7.
David Callan, A combinatorial interpretation for a super-Catalan recurrence, arXiv:math/0408117 [math.CO], 2004.
Ira M. Gessel, Super ballot numbers, J. Symbolic Comp., 14 (1992), 179-194
Ira M. Gessel and Guoce Xin, A Combinatorial Interpretation of the Numbers 6(2n)!/n!(n+2)!, Journal of Integer Sequences, Vol. 8 (2005), Article 05.2.3.
Paveł Szabłowski, Beta distributions whose moment sequences are related to integer sequences listed in the OEIS, Contrib. Disc. Math. (2024) Vol. 19, No. 4, 85-109. See p. 96.

Row 2 of the array A135573.

Cf. A001622, A002422, A007054, A348893.

seq(10*(2*n)!/(n!)^2/binomial(n+3,n), n=0..26); # Zerinvary Lajos, Jun 28 2007

Table[60(2n)!/(n!(n+3)!), {n, 0, 30}] (* Jean-François Alcover, Jun 02 2019 *)

a(n)=if(n<0, 0, 60*(2*n)!/n!/(n+3)!) /* Michael Somos, Feb 19 2006 */

{a(n)=if(n<0, 0, n*=2; n!*polcoeff( 10*besseli(3,2*x+x*O(x^n)), n))} /* Michael Somos, Feb 19 2006 */

def A007272(n): return -(-4)^(3 + n)*binomial(5/2, 3 + n)/2
print([A007272(n) for n in range(30)])  # Peter Luschny, Nov 04 2021

G.f.: (11-32*x+9*sqrt(1-4*x))/(1-3*x+(1-x)*sqrt(1-4*x)).
E.g.f.: Sum_{n>=0} a(n)*x^(2n)/(2n)! = 60*BesselI(3, 2x)/x^3.
E.g.f.: (BesselI(0, 2*x)*(2*x+16*x^2)-BesselI(1, 2*x)*(2+6*x+16*x^2))*exp(2*x)/x^2.
Integral representation as the n-th moment of a positive function on [0, 4]: a(n) = Integral_{x=0..4} x^n*(4-x)^(5/2)/(2*Pi*x^(1/2)) dx. This representation is unique. - Karol A. Penson, Dec 04 2001
a(n) = 10*(2*n)!*[x^(2*n)](hypergeometric([],[4],x^2)). - Peter Luschny, Feb 01 2015
(n+3)*a(n) +2*(-2*n+1)*a(n-1)=0. - R. J. Mathar, Mar 06 2018
a(n) = -(-4)^(3+n)*binomial(5/2, 3+n)/2. - Peter Luschny, Nov 04 2021
From Amiram Eldar, Mar 24 2022: (Start)
Sum_{n>=0} 1/a(n) = 4/9 + 28*Pi/(3^5*sqrt(3)).
Sum_{n>=0} (-1)^n/a(n) = 38/1875 - 56*log(phi)/(5^4*sqrt(5)), where phi is the golden ratio (A001622). (End)
From Peter Bala, Mar 11 2023: (Start)
a(n) = Sum_{k = 0..2} (-1)^k*4^(2-k)*binomial(n,k)*Catalan(n+k) = 16*Catalan(n) - 8*Catalan(n+1) + Catalan(n+2), where Catalan(n) = A000108(n). Thus a(n) is an integer for all n.
a(n) is odd if n = 2^k - 3, k >= 2, else a(n) is even. (End)

A002422 Expansion of (1-4*x)^(5/2).

Original entry on oeis.org

1, -10, 30, -20, -10, -12, -20, -40, -90, -220, -572, -1560, -4420, -12920, -38760, -118864, -371450, -1179900, -3801900, -12406200, -40940460, -136468200, -459029400, -1556708400, -5318753700, -18296512728, -63334082520

Offset: 0

N. J. A. Sloane

sign

A. Fletcher, J. C. P. Miller, L. Rosenhead and L. J. Comrie, An Index of Mathematical Tables. Vols. 1 and 2, 2nd ed., Blackwell, Oxford and Addison-Wesley, Reading, MA, 1962, Vol. 1, p. 55.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
T. N. Thiele, Interpolationsrechnung. Teubner, Leipzig, 1909, p. 164.

G. C. Greubel, Table of n, a(n) for n = 0..1000 (terms 0..100 from Vincenzo Librandi)
N. J. A. Sloane, Notes on A984 and A2420-A2424

Cf. A007054, A004001, A002420, A002421, A002423, A002424, A007272, A001622.

R:=PowerSeriesRing(Rationals(), 30); Coefficients(R!( (1-4*x)^(5/2) )); // G. C. Greubel, Jul 03 2019

A002422 := n -> -(15/8)*4^n*GAMMA(n-5/2)/(sqrt(Pi)*GAMMA(1+n)):
seq(A002422(n), n=0..26); # Peter Luschny, Dec 14 2015

CoefficientList[Series[(1-4x)^{5/2},{x,0,30}],x] (* Vincenzo Librandi, Jun 11 2012 *)

vector(30, n, n--; (-4)^n*binomial(5/2, n)) \\ G. C. Greubel, Jul 03 2019

[(-4)^n*binomial(5/2, n) for n in (0..30)] # G. C. Greubel, Jul 03 2019

a(n+3) = -2 * A007272(n).
a(n) = Sum_{m=0..n} binomial(n, m) * K_m(6), where K_m(x) = K_m(n, 2, x) is a Krawtchouk polynomial. - Alexander Barg (abarg(AT)research.bell-labs.com).
a(n) ~ -15/8*Pi^(-1/2)*n^(-7/2)*2^(2*n)*{1 + 35/8*n^-1 + ...}. - Joe Keane (jgk(AT)jgk.org), Nov 22 2001
a(n) = -(15/8)*4^n*Gamma(n-5/2)/(sqrt(Pi)*Gamma(1+n)). - Peter Luschny, Dec 14 2015
a(n) = (-4)^n*binomial(5/2, n). - Peter Luschny, Oct 22 2018
D-finite with recurrence: n*a(n) +2*(-2*n+7)*a(n-1)=0. - R. J. Mathar, Jan 16 2020
From Amiram Eldar, Mar 24 2022: (Start)
Sum_{n>=0} 1/a(n) = 32/45 - 14*Pi/(3^5*sqrt(3)).
Sum_{n>=0} (-1)^n/a(n) = 2144/1875 - 28*log(phi)/(5^4*sqrt(5)), where phi is the golden ratio (A001622). (End)

A002423 Expansion of (1-4*x)^(7/2).

Original entry on oeis.org

1, -14, 70, -140, 70, 28, 28, 40, 70, 140, 308, 728, 1820, 4760, 12920, 36176, 104006, 305900, 917700, 2801400, 8684340, 27293640, 86843400, 279409200, 908079900, 2978502072, 9851968392, 32839894640

Offset: 0

N. J. A. Sloane

A. Fletcher, J. C. P. Miller, L. Rosenhead and L. J. Comrie, An Index of Mathematical Tables. Vols. 1 and 2, 2nd ed., Blackwell, Oxford and Addison-Wesley, Reading, MA, 1962, Vol. 1, p. 55.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
T. N. Thiele, Interpolationsrechnung. Teubner, Leipzig, 1909, p. 164.

Vincenzo Librandi, Table of n, a(n) for n = 0..1000
N. J. A. Sloane, Notes on A984 and A2420-A2424

Cf. A007054, A004001, A002420, A002421, A002422, A002424, A007272, A001622.

R:=PowerSeriesRing(Rationals(), 30); Coefficients(R!( (1-4*x)^(7/2) )); // G. C. Greubel, Jul 03 2019

A002423 := n -> (105/16)*4^n*GAMMA(-7/2+n)/(sqrt(Pi)*GAMMA(1+n)):
seq(A002423(n), n=0..27); # Peter Luschny, Dec 14 2015

CoefficientList[Series[(1-4*x)^(7/2),{x,0,30}],x] (* Jean-François Alcover, Mar 21 2011 *)
Table[(4^(-1+x) Pochhammer[-(7/2),-1+x])/Pochhammer[1,-1+x],{x,30}] (* Harvey P. Dale, Jul 13 2011 *)

vector(30, n, n--; (-4)^n*binomial(7/2, n)) \\ G. C. Greubel, Jul 03 2019

[(-4)^n*binomial(7/2, n) for n in (0..30)] # G. C. Greubel, Jul 03 2019

a(n) = Sum_{m=0..n} binomial(n, m) * K_m(8), where K_m(x) = K_m(n, 2, x) is a Krawtchouk polynomial. - Alexander Barg (abarg(AT)research.bell-labs.com)
a(n) ~ 105*4^(n-2)/(sqrt(Pi)*n^(9/2)). - Vaclav Kotesovec, Jul 28 2013
a(n) = (105/16)*4^n*Gamma(-7/2+n)/(sqrt(Pi)*Gamma(1+n)). - Peter Luschny, Dec 14 2015
a(n) = (-4)^n * binomial(7/2, n). - G. C. Greubel, Jul 03 2019
D-finite with recurrence: n*a(n) +2*(-2*n+9)*a(n-1)=0. - R. J. Mathar, Jan 16 2020
From Amiram Eldar, Mar 24 2022: (Start)
Sum_{n>=0} 1/a(n) = 36/35 + 2*Pi/(3^4*sqrt(3)).
Sum_{n>=0} (-1)^n/a(n) = 23932/21875 - 36*log(phi)/(5^5*sqrt(5)), where phi is the golden ratio (A001622). (End)

A002424 Expansion of (1-4*x)^(9/2).

Original entry on oeis.org

1, -18, 126, -420, 630, -252, -84, -72, -90, -140, -252, -504, -1092, -2520, -6120, -15504, -40698, -110124, -305900, -869400, -2521260, -7443720, -22331160, -67964400, -209556900, -653817528, -2062039896, -6567978928, -21111360840

Offset: 0

N. J. A. Sloane

A. Fletcher, J. C. P. Miller, L. Rosenhead and L. J. Comrie, An Index of Mathematical Tables. Vols. 1 and 2, 2nd ed., Blackwell, Oxford and Addison-Wesley, Reading, MA, 1962, Vol. 1, p. 55.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
T. N. Thiele, Interpolationsrechnung. Teubner, Leipzig, 1909, p. 164.

Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Alexander Barg, Stolarsky's invariance principle for finite metric spaces, arXiv:2005.12995 [math.CO], 2020.
N. J. A. Sloane, Notes on A984 and A2420-A2424.

Cf. A001622, A002420, A002421, A002422, A002423, A004001, A007054, A007272.

R:=PowerSeriesRing(Rationals(), 30); Coefficients(R!( (1-4*x)^(9/2) )); // G. C. Greubel, Jul 03 2019

A002424 := n -> -(945/32)*4^n*GAMMA(-9/2+n)/(sqrt(Pi)*GAMMA(1+n)):
seq(A002424(n),n=0..28); # Peter Luschny, Dec 14 2015

CoefficientList[Series[(1-4x)^(9/2),{x,0,30}],x] (* Harvey P. Dale, Dec 27 2011 *)

my(x='x+O('x^30)); Vec((1-4*x)^(9/2)) \\ Altug Alkan, Dec 14 2015

vector(30, n, n--; (-4)^n*binomial(9/2, n)) \\ G. C. Greubel, Jul 03 2019

[(-4)^n*binomial(9/2, n) for n in (0..30)] # G. C. Greubel, Jul 03 2019

a(n) = Sum_{m=0..n} binomial(n, m) * K_m(10), where K_m(x) = K_m(n, 2, x) is a Krawtchouk polynomial. - Alexander Barg, abarg(AT)research.bell-labs.com.
a(n) = -(945/32)*4^n*Gamma(-9/2+n)/(sqrt(Pi)*Gamma(1+n)). - Peter Luschny, Dec 14 2015
a(n) = (-4)^n*binomial(9/2, n). - G. C. Greubel, Jul 03 2019
D-finite with recurrence: n*a(n) +2*(-2*n+11)*a(n-1)=0. - R. J. Mathar, Jan 16 2020
From Amiram Eldar, Mar 25 2022: (Start)
Sum_{n>=0} 1/a(n) = 32/35 - 22*Pi/(3^7*sqrt(3)).
Sum_{n>=0} (-1)^n/a(n) = 1050752/984375 - 44*log(phi)/(5^6*sqrt(5)), where phi is the golden ratio (A001622). (End)

A135573 Array T(n,m) of super ballot numbers read along ascending antidiagonals.

Original entry on oeis.org

1, 3, 1, 10, 2, 2, 35, 5, 3, 5, 126, 14, 6, 6, 14, 462, 42, 14, 10, 14, 42, 1716, 132, 36, 20, 20, 36, 132, 6435, 429, 99, 45, 35, 45, 99, 429, 24310, 1430, 286, 110, 70, 70, 110, 286, 1430, 92378, 4862, 858, 286, 154, 126, 154, 286, 858, 4862

Offset: 0

R. J. Mathar, Feb 23 2008

First row is A000108. 2nd row is A007054. 3rd row and 4th column are essentially A007272.
1st column is A001700. 2nd column is essentially A000108. 3rd column is A007054.
Main diagonal is A000984.

			Array with rows n >= 0 and columns m >= 0 starts:
[n\m]  0    1    2    3    4    5    6     7     8  ...
-------------------------------------------------------
[0]    1    1    2    5   14   42  132   429  1430  ...  [A000108]
[1]    3    2    3    6   14   36   99   286   858  ...  [A007054]
[2]   10    5    6   10   20   45  110   286   780  ...  [A007272]
[3]   35   14   14   20   35   70  154   364   910  ...  [A348893]
[4]  126   42   36   45   70  126  252   546  1260  ...  [A348898]
[5]  462  132   99  110  154  252  462   924  1980  ...  [A348899]
[6] 1716  429  286  286  364  546  924  1716  3432  ...
...
Seen as a triangle:
[0] 1;
[1] 3,    1;
[2] 10,   2,   2;
[3] 35,   5,   3,  5;
[4] 126,  14,  6,  6,  14;
[5] 462,  42,  14, 10, 14, 42;
[6] 1716, 132, 36, 20, 20, 36, 132;
[7] 6435, 429, 99, 45, 35, 45, 99,  429.
.
T(20, 100000) = 2.442634...*10^60129. Asymptotic formula: 2.442627..*10^60129.

G. C. Greubel, Table of n, a(n) for the first 50 antidiagonals
E. Allen and I. Gheorghiciuc, A Weighted Interpretation for the Super Catalan Numbers, J. Int. Seq. 17 (2014) # 14.10.7, Table 1.
Ira M. Gessel, Super ballot numbers, J. Symb. Comput. vol 14, iss 2-3 (1992) pp 179-194.

Cf. A000108, A007054, A000984, A348893, A348898, A348899.

Cf. A000984 (main diagonal), A001700 (column 0), A082590 (sum of antidiagonals).

T := proc(n,m) (2*n+1)!/n!*(2*m)!/m!/(m+n+1)! ; end proc:
for d from 0 to 12 do for c from 0 to d do printf("%d, ",T(d-c,c)) ; od: od:
# Alternatively, printed as rows:
A135573 := (n, m) -> (1/(2*Pi))*int(x^m*(4-x)^(n+1/2)*x^(-1/2), x=0..4):
for n from 0 to 9 do seq(A135573(n, m), m = 0..9) od; # Peter Luschny, Nov 03 2021

T[n_, m_] := (2*n+1)!/n!*(2*m)!/m!/(m+n+1)!; Table[T[n-m, m], {n, 0, 12}, {m, 0, n}] // Flatten (* Jean-François Alcover, Jan 06 2014, after Maple *)
T[n_, m_] := 4^(m+n) Hypergeometric2F1[1/2+n, 1/2-m, 3/2+n, 1] / ((2 n + 1) Pi);
Table[T[n - m + 1, m], {n, 0, 9}, {m, 0, n}] // Flatten (* Peter Luschny, Nov 03 2021 *)

def T(n, m): return (-1)^m*4^(n + 1 + m)*binomial(n + 1/2, n + 1 + m)/2
for n in range(7): print([T(n, m) for m in range(9)]) # Peter Luschny, Nov 04 2021

T(n, m) = (2*n + 1)!*(2*m)! / (n!*m!*(m + n + 1)!).
From Peter Luschny, Nov 03 2021: (Start)
T(n, m) = (1/(2*Pi))*Integral_{x=0..4} x^m*(4 - x)^(n + 1/2)*x^(-1/2). These are integral representations of the n-th moment of a positive function on [0, 4]. The representations are unique.
T(n, m) = 4^(m + n)*hypergeom([1/2 + n, 1/2 - m], [3/2 + n], 1)/((2*n + 1)*Pi).
For fixed n and m -> oo: T(n, m) ~ (1/(2*Pi))*4^(n + m + 1)*(Gamma(3/2 + n) / m^(3/2 + n))*(1 - (2*n + 3)^2 / (8*m)) . (End)
T(n, m) = (-1)^m*4^(n + 1 + m)*binomial(n + 1/2, n + 1 + m)/2. - Peter Luschny, Nov 04 2021
From  Peter Bala, Mar 12 2023: (Start)
T(n,m) = 2*(2*n + 1 )/(n + m + 1) * T(n-1,m) with T(0,m) = Catalan(m), where Catalan(m) = A000108(m).
T(n,m) = Sum_{k = 0..n} (-1)^k*4^(n-k)*binomial(n,k)*Catalan(m+k) (easily verified using Maple's sumrecursion command). Thus T(n,m) is an integer. (End)

cp's OEIS Frontend

A038665 Convolution of A007054 (super ballot numbers) with A000984 (central binomial coefficients).

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A038679 Convolution of A007054 (Super ballot numbers) with A000302 (powers of 4).

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A005700 a(n) = C(n)*C(n+2) - C(n+1)^2 where C() are the Catalan numbers A000108.

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A000257 Number of rooted bicubic maps: a(n) = (8*n-4)*a(n-1)/(n+2) for n >= 2, a(0) = a(1) = 1.

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A002421 Expansion of (1-4*x)^(3/2) in powers of x.

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A007272 Super ballot numbers: 60*(2n)!/(n!*(n+3)!).

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A000257 Number of rooted bicubic maps: a(n) = (8n-4)a(n-1)/(n+2) for n >= 2, a(0) = a(1) = 1.

A007272 Super ballot numbers: 60(2n)!/(n!(n+3)!).