cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 32 results. Next

A151334 Duplicate of A005789.

Original entry on oeis.org

1, 1, 5, 42, 462, 6006, 87516, 1385670, 23371634, 414315330, 7646001090, 145862174640, 2861142656400, 57468093927120
Offset: 0

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Author

Keywords

A060854 Array T(m,n) read by antidiagonals: T(m,n) (m >= 1, n >= 1) = number of ways to arrange the numbers 1,2,...,m*n in an m X n matrix so that each row and each column is increasing.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 5, 5, 1, 1, 14, 42, 14, 1, 1, 42, 462, 462, 42, 1, 1, 132, 6006, 24024, 6006, 132, 1, 1, 429, 87516, 1662804, 1662804, 87516, 429, 1, 1, 1430, 1385670, 140229804, 701149020, 140229804, 1385670, 1430, 1, 1, 4862, 23371634, 13672405890, 396499770810, 396499770810, 13672405890, 23371634, 4862, 1
Offset: 1

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Author

R. H. Hardin, May 03 2001

Keywords

Comments

Multidimensional Catalan numbers; a special case of the "hook-number formula".
Number of paths from (0,0,...,0) to (n,n,...,n) in m dimensions, all coordinates increasing: if (x_1,x_2,...,x_m) is on the path, then x_1 <= x_2 <= ... <= x_m. Number of ways to label an n by m array with all the values 1..n*m such that each row and column is strictly increasing. Number of rectangular Young Tableaux. Number of linear extensions of the n X m lattice (the divisor lattice of a number having exactly two prime divisors). - Mitch Harris, Dec 27 2005
Given m*n lines in a {(m + 1)(n - 1)}-dimensional space, T(m, n) is the number of {n*(m-1)-1}-dimensional spaces cutting these lines in points (see Fontanari and Castelnuovo). - Stefano Spezia, Jun 19 2022

Examples

			Array begins:
  1,   1,     1,         1,            1,                1, ...
  1,   2,     5,        14,           42,              132, ...
  1,   5,    42,       462,         6006,            87516, ...
  1,  14,   462,     24024,      1662804,        140229804, ...
  1,  42,  6006,   1662804,    701149020,     396499770810, ...
  1, 132, 87516, 140229804, 396499770810, 1671643033734960, ...
		

References

  • Guido Castelnuovo, Numero degli spazi che segano più rette in uno spazio ad n dimensioni, Rendiconti della R. Accademia dei Lincei, s. IV, vol. V, 4 agosto 1889. In Guido Castelnuovo, Memorie scelte, Zanichelli, Bologna 1937, pp. 55-64 (in Italian).
  • R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Example 7.23.19(b).

Crossrefs

Rows give A000108 (Catalan numbers), A005789, A005790, A005791, A321975, A321976, A321977, A321978.
Diagonals give A039622, A060855, A060856.
Cf. A227578. - Alois P. Heinz, Jul 18 2013
Cf. A321716.

Programs

  • Maple
    T:= (m, n)-> (m*n)! * mul(i!/(m+i)!, i=0..n-1):
    seq(seq(T(n, 1+d-n), n=1..d), d=1..10);
  • Mathematica
    maxm = 10; t[m_, n_] := Product[k!, {k, 0, n - 1}]*(m*n)! / Product[k!, {k, m, m + n - 1}]; Flatten[ Table[t[m + 1 - n, n], {m, 1, maxm}, {n, 1, m}]] (* Jean-François Alcover, Sep 21 2011 *)
    Table[ BarnesG[n+1]*(n*(m-n+1))!*BarnesG[m-n+2] / BarnesG[m+2], {m, 1, 10}, {n, 1, m}] // Flatten (* Jean-François Alcover, Jan 30 2016 *)
  • PARI
    {A(i, j) = if( i<0 || j<0, 0, (i*j)! / prod(k=1, i+j-1, k^vecmin([k, i, j, i+j-k])))}; /* Michael Somos, Jan 28 2004 */

Formula

T(m, n) = 0!*1!*..*(n-1)! *(m*n)! / ( m!*(m+1)!*..*(m+n-1)! ).
T(m, n) = A000142(m*n)*A000178(m-1)*A000178(n-1)/A000178(m+n-1) = A000142(A004247(m, n)) * A007318(m+n, n)/A009963(m+n, n). - Henry Bottomley, May 22 2002

Extensions

More terms from Frank Ellermann, May 21 2001

A039622 Number of n X n Young tableaux.

Original entry on oeis.org

1, 1, 2, 42, 24024, 701149020, 1671643033734960, 475073684264389879228560, 22081374992701950398847674830857600, 220381378415074546123953914908618547085974856000, 599868742615440724911356453304513631101279740967209774643120000
Offset: 0

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Author

Keywords

Comments

Number of arrangements of 1,2,...,n^2 in an n X n array such that each row and each column is increasing. The problem for a 5 X 5 array was recently posed and solved in the College Mathematics Journal. See the links.
This is the factor g_n that appears in a conjectured formula for 2n-th moment of the Riemann zeta function on the critical line. (See Conrey articles.) - Michael Somos, Apr 15 2003 [Comment revised by N. J. A. Sloane, Jun 21 2016]
Number of linear extensions of the n X n lattice. - Mitch Harris, Dec 27 2005

Examples

			Using the hook length formula, a(4) = (16)!/(7*6^2*5^3*4^4*3^3*2^2) = 24024.
		

References

  • M. du Sautoy, The Music of the Primes, Fourth Estate / HarperCollins, 2003; see p. 284.

Crossrefs

Main diagonal of A060854.
Also a(2)=A000108(2), a(3)=A005789(3), a(4)=A005790(4), a(5)=A005791(5).

Programs

  • Magma
    A039622:= func< n | n eq 0 select 1 else Factorial(n^2)*(&*[Factorial(j)/Factorial(n+j): j in [0..n-1]]) >;
    [A039622(n): n in [0..12]]; // G. C. Greubel, Apr 21 2021
    
  • Maple
    a:= n-> (n^2)! *mul(k!/(n+k)!, k=0..n-1):
    seq(a(n), n=0..12);  # Alois P. Heinz, Apr 10 2012
  • Mathematica
    a[n_]:= (n^2)!*Product[ k!/(n+k)!, {k, 0, n-1}]; Table[ a[n], {n, 0, 12}] (* Jean-François Alcover, Dec 06 2011, after Pari *)
  • PARI
    a(n)=(n^2)!*prod(k=0,n-1,k!/(n+k)!)
    
  • Sage
    def A039622(n): return factorial(n^2)*product( factorial(j)/factorial(n+j) for j in (0..n-1))
    [A039622(n) for n in (0..12)] # G. C. Greubel, Apr 21 2021

Formula

a(n) = (n^2)! / Product_{k=1..2n-1} k^(n - |n-k|).
a(n) = 0!*1!*...*(k-1)! *(k*n)! / ( n!*(n+1)!*...*(n+k-1)! ) for k=n.
a(n) = A088020(n)/A107254(n) = A088020(n)*A000984(n)/A079478(n). - Henry Bottomley, May 14 2005
a(n) = A153452(prime(n)^n). - Naohiro Nomoto, Jan 01 2009
a(n) ~ sqrt(Pi) * n^(n^2+11/12) * exp(n^2/2+1/12) / (A * 2^(2*n^2-7/12)), where A = 1.28242712910062263687534256886979... is the Glaisher-Kinkelin constant (see A074962). - Vaclav Kotesovec, Feb 10 2015
From Peter Luschny, May 20 2019: (Start)
a(n) = (G(1+n)*G(2+n)^(2-n)*(n^2)!*(G(3+n)/Gamma(2+n))^(n-1))/(G(1+2*n)*n!) where G(x) is the Barnes G function.
a(n) = A127223(n) / A107252(n). (End)
a(n) = (Gamma(n^2 +1)/Gamma(n+1))*(G(n+1)*G(n+2)/G(2*n+1)), where G(n) is the Barnes G-function. - G. C. Greubel, Apr 21 2021
a(n+2) = (n+2) * A060856(n+1) for n >= 0. - Tom Copeland, May 30 2022

A005790 4-dimensional Catalan numbers.

Original entry on oeis.org

1, 1, 14, 462, 24024, 1662804, 140229804, 13672405890, 1489877926680, 177295473274920, 22661585038594320, 3073259571003214320, 438091463242348309440, 65166105157299311029200, 10056663345892631910888600, 1602608179958939072505281850, 262708662267696303439658400600
Offset: 0

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Author

Keywords

Comments

Number of standard tableaux of shape (n,n,n,n). - Emeric Deutsch, May 13 2004
The prime terms (as defined in A268538) are 1, 1, 10, 320, 16764, 1171355, 99315236, 9691755128, 1053114415100, ... - R. J. Mathar, Feb 27 2018

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • Snover, Stephen L.; Troyer, Stephanie F.; A four-dimensional Catalan formula. Proceedings of the Nineteenth Manitoba Conference on Numerical Mathematics and Computing (Winnipeg, MB, 1989). Congr. Numer. 75 (1990), 123-126.

Crossrefs

A row of A060854.
Cf. A000108 (Catalan numbers), A005789, A005791.

Programs

  • Magma
    [12*Factorial(4*n)/(Factorial(n)*Factorial(n+1)*Factorial(n+2) *Factorial(n+3)): n in [0..20]]; // Vincenzo Librandi, Nov 23 2018
    
  • Maple
    a:= n-> (4*n)! * mul(i!/(4+i)!, i=0..n-1):
    seq(a(n), n=0..20);  # Alois P. Heinz, Jul 25 2012
  • Mathematica
    Table[12*(4*n)!/(n!*(n+1)!*(n+2)!*(n+3)!), {n, 0, 20}] (* Vaclav Kotesovec, Nov 18 2016 *)
  • PARI
    vector(20, n, n--; 12*(4*n)!/(n!*(n+1)!*(n+2)!*(n+3)!)) \\ G. C. Greubel, Nov 23 2018
    
  • Sage
    [12*factorial(4*n)/(factorial(n)*factorial(n+1)*factorial(n+2) *factorial(n+3)) for n in range(20)] # G. C. Greubel, Nov 23 2018

Formula

a(n) = 12*(4*n)!/(n! *(n+1)! *(n+2)! *(n+3)!).
G.f.: 4_F_3 ( [ 1, 3/2, 5/4, 7/4 ]; [ 3, 4, 5 ]; 256 x ).
a(n) ~ 3*2^(8*n+3/2)/(Pi^(3/2)*n^(15/2)). - Vaclav Kotesovec, Nov 18 2016
E.g.f.: 3F3(1/4,1/2,3/4; 2,3,4; 256*x) - 1. - Ilya Gutkovskiy, Oct 13 2017
(n+3)*(n+2)*(n+1)*a(n) -8*(4*n-3)*(2*n-1)*(4*n-1)*a(n-1)=0. - R. J. Mathar, Mar 04 2018

Extensions

a(0)=1 prepended by Seiichi Manyama, Nov 23 2018

A005791 5-dimensional Catalan numbers.

Original entry on oeis.org

1, 1, 42, 6006, 1662804, 701149020, 396499770810, 278607172289160, 231471904322784840, 219738059326729823880, 232553551737813227594400, 269396678720275351794712800, 336839101096824285057473785200, 449620757769949216266129125515200
Offset: 0

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Author

Keywords

Comments

Number of standard tableaux of shape (n,n,n,n,n). - Emeric Deutsch, May 13 2004

References

  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
  • Snover, Stephen L.; Troyer, Stephanie F.; A four-dimensional Catalan formula. Proceedings of the Nineteenth Manitoba Conference on Numerical Mathematics and Computing (Winnipeg, MB, 1989). Congr. Numer. 75 (1990), 123-126.

Crossrefs

A row of A060854.

Programs

  • Maple
    a:= n-> (5*n)! * mul(i!/(n+i)!, i=0..4):
    seq(a(n), n=0..20);  # Alois P. Heinz, Jul 23 2017
  • Mathematica
    Table[288*(5*n)!/(n!*(n+1)!*(n+2)!*(n+3)!*(n+4)!), {n, 1, 20}] (* Vaclav Kotesovec, Nov 18 2016 *)

Formula

a(n) = 0!*1!*..*(k-1)! *(k*n)! / ( n!*(n+1)!*..*(n+k-1)! ) for k=5.
(n+4)*(n+3)*(n+2)*(n+1)*a(n) -5*(5*n-4)*(5*n-3)*(5*n-2)*(5*n-1)*a(n-1)=0. - R. J. Mathar, Aug 10 2015
G.f.: x*5F4(1,6/5,7/5,8/5,9/5;3,4,5,6;3125*x). - R. J. Mathar, Aug 10 2015
a(n) ~ 72*5^(5*n+1/2)/(Pi^2*n^12). - Vaclav Kotesovec, Nov 18 2016
E.g.f.: 4F4(1/5,2/5,3/5,4/5; 2,3,4,5; 3125*x). - Ilya Gutkovskiy, Oct 13 2017

Extensions

a(0)=1 prepended by Alois P. Heinz, Jul 23 2017

A007724 Even minus odd extensions of truncated 3 X 2n grid diagram.

Original entry on oeis.org

2, 12, 110, 1274, 17136, 255816, 4124406, 70549050, 1264752060, 23555382240, 452806924752, 8939481277552, 180551099694400, 3719061442253520, 77933728043586630, 1658001861319441050, 35749633305661575300, 780123576993991461000, 17208112644166765652100
Offset: 2

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Author

Keywords

Comments

Number of standard tableaux of shapes (n-1,n-1,k), k=0,1,...,n-1. Example: a(3)=12 because there are 2, 5 and 5 standard tableaux of shapes (2,2), (2,2,1) and (2,2,2), respectively. - Emeric Deutsch, May 25 2004
From Joel B. Lewis, Oct 05 2009: (Start)
Also the number of standard shifted Young tableaux of shape (n+1, n, n-1).
Also the number of 2143-avoiding up-down permutations of length 2n - 1. (End)

Crossrefs

Cf. A003121.
2143-avoiding up-down permutations of length 2n are given by A005789. - Joel B. Lewis, Oct 05 2009
After corrections, is very similar to A217800.

Programs

  • Maple
    A007724 := proc(n)
        combinat[multinomial](3*n,n-1,n,n+1)/n/(2*n-1)/(2*n+1) ;
    end proc:
    seq(A007724(n),n=2..40) ; # R. J. Mathar, Jul 07 2023
  • Mathematica
    Table[(3*n)!/((n-1)!*n!*(n+1)!)/(n*(2*n-1)*(2*n+1)),{n,2,10}] (* Vaclav Kotesovec, Nov 13 2014 *)
    Table[(-1)^n HypergeometricPFQ[{-2 - 2 n, -2 n, -2 n - 1}, {2, 3}, 1], {n, 19}] (* Michael De Vlieger, Aug 22 2016 *)
  • PARI
    {a(n) = if(n<2, 0, (3*n)!/((2*n+1) * (2*n-1) * (n+1)! * n!^2))}; /* Michael Somos, Jul 04 2020 */

Formula

a(n) = multinomial(3n; n-1, n, n+1)/(n(2n-1)(2n+1)).
a(n) ~ 3^(3*n+1/2) / (8*Pi*n^4). - Vaclav Kotesovec, Nov 13 2014
D-finite with recurrence n*(n+1)*(2*n+1)*a(n) -3*(3*n-1)*(2*n-3)*(3*n-2)*a(n-1)=0. - R. J. Mathar, Jul 07 2023

Extensions

More terms from James Sellers, Dec 24 1999
a(16)-a(18) corrected and a(19)-a(20) added by Alois P. Heinz, Aug 22 2016

A215204 Number A(n,k) of solid standard Young tableaux of cylindrical shape lambda X k, where lambda ranges over all partitions of n; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 2, 3, 1, 1, 4, 4, 5, 1, 1, 10, 26, 10, 7, 1, 1, 28, 276, 258, 26, 11, 1, 1, 84, 3740, 14318, 3346, 76, 15, 1, 1, 264, 58604, 1161678, 1214358, 54108, 232, 22, 1, 1, 858, 1010616, 118316062, 741215012, 150910592, 1054256, 764, 30
Offset: 0

Views

Author

Alois P. Heinz, Aug 05 2012

Keywords

Examples

			Square array A(n,k) begins:
:  1,  1,     1,         1,            1,                1, ...
:  1,  1,     1,         1,            1,                1, ...
:  2,  2,     4,        10,           28,               84, ...
:  3,  4,    26,       276,         3740,            58604, ...
:  5, 10,   258,     14318,      1161678,        118316062, ...
:  7, 26,  3346,   1214358,    741215012,     620383261034, ...
: 11, 76, 54108, 150910592, 840790914296, 7137345113624878, ...
		

Crossrefs

Columns k=0-5 give: A000041, A000085, A215266, A290202, A290214, A290274.
Rows n=0+1, 2-5 give: A000012, 2*A000108, 2*A005789 + A006335, 2*A005790 + 2*A213978 + A114714, 2*A005791 + 2*A215220 + 2*A213932 + A214638.
Main diagonal gives A290225.

Programs

  • Maple
    b:= proc(l) option remember; local m; m:= nops(l);
          `if`({map(x-> x[], l)[]}minus{0}={}, 1, add(add(`if`(l[i][j]>
          `if`(i=m or nops(l[i+1])
          `if`(nops(l[i])=j, 0, l[i][j+1]), b(subsop(i=subsop(
           j=l[i][j]-1, l[i]), l)), 0), j=1..nops(l[i])), i=1..m))
        end:
    g:= proc(n, i, k, l) `if`(n=0 or i=1, b(map(x-> [k$x], [l[], 1$n])),
           add(g(n-i*j, i-1, k, [l[], i$j]), j=0..n/i))
        end:
    A:= (n, k)-> g(n, n, k, []):
    seq(seq(A(n, d-n), n=0..d), d=0..10);
  • Mathematica
    b[l_] := b[l] = With[{m = Length[l]}, If[Union[l // Flatten] ~Complement~ {0} == {}, 1, Sum[Sum[If[l[[i, j]] > If[i == m || Length[l[[i + 1]]] < j, 0, l[[i + 1, j]]] && l[[i, j]] > If[Length[l[[i]]] == j, 0, l[[i, j + 1]]], b[ReplacePart[l, i -> ReplacePart[l[[i]], j -> l[[i, j]] - 1]]], 0], {j, 1, Length[l[[i]]]}], {i, 1, m}]]];
    g[n_, i_, k_, l_] := If[n == 0 || i == 1, b[Table[k, {#}]& /@ Join[l, Table[1, {n}]]], Sum[g[n - i*j, i - 1, k, Join[l, Table[i, {j}]]], {j, 0, n/i}]];
    A[n_, k_] := g[n, n, k, {}];
    Table[Table[A[n, d - n], {n, 0, d}], {d, 0, 10}] // Flatten (* Jean-François Alcover, Sep 24 2022, after Alois P. Heinz *)

A217800 Number of alternating permutations on 2n+1 letters that avoid a certain pattern of length 4 (see Lewis, 2012, Appendix, for precise definition).

Original entry on oeis.org

1, 2, 12, 110, 1274, 17136, 255816, 4124406, 70549050, 1264752060, 23555382240, 452806924752, 8939481277552, 180551099694400, 3719061442253520, 77933728043586630, 1658001861319441050, 35749633305661575300, 780123576993991461000, 17208112644166765652100
Offset: 0

Views

Author

N. J. A. Sloane, Oct 12 2012

Keywords

Comments

1 together with A007724. - Omar E. Pol, Aug 22 2016

Crossrefs

Programs

  • Magma
    [Factorial(3*n+3)/((4*(n+1)^2-1)*Factorial((n+1))^2*Factorial(n+ 2)): n in [0..20]]; // Vincenzo Librandi, Aug 30 2014
  • Maple
    a := n -> (-1)^n*hypergeom([-2-2*n, -2*n, -2*n-1], [2, 3], 1):
    seq(round(evalf(a(n), 32)), n=0..20); # Peter Luschny, Aug 29 2014
  • Mathematica
    Table[(3 n + 3)!/((4 (n + 1)^2 - 1) ((n + 1)!)^2 (n + 2)!), {n, 0, 20}] (* Vincenzo Librandi, Aug 30 2014 *)
    Table[(-1)^n HypergeometricPFQ[{-2 - 2 n, -2 n, -2 n - 1}, {2, 3}, 1], {n, 0, 20}] (* Michael De Vlieger, Aug 22 2016 *)
  • PARI
    a(n) = (3*n+3)!/((4*(n+1)^2-1)*((n+1)!)^2*(n+2)!); \\ Michel Marcus, Aug 10 2014
    

Formula

From Karol A. Penson, Aug 10 2014: (Start)
O.g.f.(in Maple notation): hypergeom([1/2, 1, 4/3, 5/3], [2, 5/2, 3], 27*z);a(n) ~ (1/93312)*sqrt(3)*27^n*(314928*n^4-1644624*n^3+5545260*n^2 -15387660*n+38310503)/(Pi*n^8), for n -> infinity.
Representation of a(n) as the n-th power moment of a positive function on the segment [0,27]:
a(n) = int(x^n*W(x),x=0..27),n=0,1,2..., where
W(x) = 1/(Pi*sqrt(x))+sqrt(x)/Pi-(9/20)*sqrt(3)*2^(1/3)* hypergeom([-2/3, -1/6, 1/3], [2/3, 11/6], (1/27)*x)*x^(1/3)/ (sqrt(Pi)*Gamma(5/6)*Gamma(2/3))-(27/56)*2^(2/3)*Gamma(5/6) *Gamma(2/3)*hypergeom([-1/3, 1/6, 2/3], [4/3, 13/6], (1/27)*x)* x^(2/3)/Pi^(5/2).
W(x) for x->0 has the singularity 1/sqrt(x), W(27)=0.
This is the solution of the Hausdorff moment problem and is unique.
a(n) = (1/2)*(n+3)!/((4*(n+1)^2-1)*(n+1)!)*A005789(n), where A005789(n) are the three-dimensional Catalan numbers (see the Gorska and Penson link).(End)
a(n) = A006480(n+1)/((2+n)*(1+2*n)*(3+2*n)). - Peter Luschny, Aug 15 2014
a(n) = (-1)^n*hypergeom([-2-2*n,-2*n,-2*n-1],[2,3],1). - Peter Luschny, Aug 29 2014
(2*n+3)*(n+2)*(n+1)*a(n) -3*(3*n+2)*(2*n-1)*(3*n+1)*a(n-1)=0. - R. J. Mathar, Jun 14 2016
a(n) ~ 3^(3*n + 7/2) / (8*Pi*n^4). - Vaclav Kotesovec, Jun 09 2019

Extensions

More terms from Alois P. Heinz, Aug 22 2016
Merged with A241958 by R. J. Mathar, Jul 07 2023

A321975 6-dimensional Catalan numbers.

Original entry on oeis.org

1, 1, 132, 87516, 140229804, 396499770810, 1671643033734960, 9490348077234178440, 67867669180627125604080, 583692803893929928888544400, 5838544419011620940996212276800, 66244124978105851196543024492572800, 836288764382254532915188713779640302400, 11570895443447601081407359451642915869302000
Offset: 0

Views

Author

Seiichi Manyama, Nov 23 2018

Keywords

Comments

Number of n X 6 Young tableaux.

Crossrefs

Programs

  • GAP
    List([0..15],n->34560*Factorial(6*n)/Product([0..5],k->Factorial(n+k))); # Muniru A Asiru, Nov 25 2018
  • Magma
    [34560*Factorial(6*n)/(Factorial(n)*Factorial(n + 1)*Factorial(n + 2)*Factorial(n + 3)*Factorial(n + 4)*Factorial(n + 5)): n in [0..15]]; // Vincenzo Librandi, Nov 24 2018
    
  • Maple
    a:= n-> (6*n)! * mul(i!/(6+i)!, i=0..n-1):
    seq(a(n), n=0..14);  # Alois P. Heinz, Nov 25 2018
  • Mathematica
    Table[34560 (6 n)! / (n! (n + 1)! (n + 2)! (n + 3)! (n + 4)! (n + 5)!), {n, 0, 60}] (* Vincenzo Librandi, Nov 24 2018 *)
  • PARI
    {a(n) = 34560*(6*n)!/(n!*(n+1)!*(n+2)!*(n+3)!*(n+4)!*(n+5)!)}
    

Formula

a(n) = 0!*1!*...*5! * (6*n)! / ( n!*(n+1)!*...*(n+5)! ).
a(n) ~ 5 * 2^(6*n + 6) * 3^(6*n + 7/2) / (Pi^(5/2) * n^(35/2)). - Vaclav Kotesovec, Nov 23 2018

A123555 Number of standard Young tableaux of type (n+1,n,n-1).

Original entry on oeis.org

0, 2, 16, 168, 2112, 30030, 466752, 7759752, 135980416, 2485891980, 47052314400, 916847954880, 18311313000960, 373542610526280, 7761573156274560, 163893933165976200, 3510476121410184960, 76151734612882397700, 1670824967127762045600, 37036620104665392010800, 828632324276985756528000
Offset: 0

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Author

Amitai Regev (amitai.regev(AT)weizmann.ac.il), Nov 15 2006

Keywords

Comments

For n > 0, a(n) is the number of up-down permutations of length 2n + 1 with no four-term increasing subsequence. Equivalently, this is the number of up-down permutations of length 2n + 1 with no four-term decreasing subsequence; the number of down-up permutations of length 2n + 1 with no four-term increasing subsequence; and the number of down-up permutations of length 2n + 1 with no four-term decreasing subsequence. (An up-down permutation is one whose descent set is {2, 4, 6, ...}.). - Joel B. Lewis, Oct 05 2009

References

  • For definition see James and Kerber, Representation Theory of Symmetric Group, Addison-Wesley, 1981, p. 107.

Crossrefs

Cf. A011553.
For up-down permutations of even length, see A005789. [Joel B. Lewis, Oct 05 2009]

Programs

  • Mathematica
    f[n_]:=16 (3 n)!/((n-1)! (n+1)! (n+3)!)
    (* first do *) Needs["DiscreteMath`Combinatorica`"] (* then *) Table[ NumberOfTableaux@ {n + 1, n, n - 1}, {n, 0, 17}] (* Robert G. Wilson v *)
  • PARI
    for(n=0,25, print1(16*(3*n)!/((n-1)!*(n+1)!*(n+3)!), ", ")) \\ G. C. Greubel, Oct 15 2017

Formula

a(n) = 16*(3*n)!/((n-1)!*(n+1)!*(n+3)!).
(n-1)*(n+3)*(n+1)*a(n) -3*n*(3*n-1)*(3*n-2)*a(n-1)=0, n>1. - R. J. Mathar, Aug 10 2015
G.f.: 2x*3F2(5/3,4/3,2;3,5;27x). - R. J. Mathar, Aug 10 2015
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