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 1-6 of 6 results.

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

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Author

Keywords

References

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

Crossrefs

Row 2 of the array A135573.

Programs

  • Maple
    seq(10*(2*n)!/(n!)^2/binomial(n+3,n), n=0..26); # Zerinvary Lajos, Jun 28 2007
  • Mathematica
    Table[60(2n)!/(n!(n+3)!), {n, 0, 30}] (* Jean-François Alcover, Jun 02 2019 *)
  • PARI
    a(n)=if(n<0, 0, 60*(2*n)!/n!/(n+3)!) /* Michael Somos, Feb 19 2006 */
    
  • PARI
    {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 */
    
  • Sage
    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

Formula

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)

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

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Author

R. J. Mathar, Feb 23 2008

Keywords

Comments

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.

Examples

			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.
		

Crossrefs

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

Programs

  • Maple
    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
  • Mathematica
    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 *)
  • Sage
    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

Formula

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)

A361031 a(n) = (3^3)*(1*2*4*5*7*8*10*11)*(3*n)!/(n!*(n+4)!^2).

Original entry on oeis.org

11550, 2772, 4620, 15840, 81675, 550550, 4492488, 42325920, 446185740, 5148297000, 63985977000, 846321189120, 11802213457650, 172255143129300, 2615726247519000, 41127042052404000, 666874986879730860, 11114583114662181000, 189866473537245687000, 3316382259894423720000
Offset: 0

Views

Author

Peter Bala, Mar 01 2023

Keywords

Comments

Row 3 of A361027.
The central binomial numbers A000984(n) = (2*n)!/n!^2 have the property that 840*A000984(n) is divisible by (n + 1)*(n + 2)*(n + 3)*(n + 4) and the result 840*(2*n)!/(n!*(n+4)!) is the super ballot number A348893(n). Similarly, the de Bruijn numbers A006480(n) = (3*n)!/n!^3 have the property that 6652800 * A006480(n) is divisible by ((n + 1)*(n + 2)*(n + 3)*(n + 4))^2.

Crossrefs

Programs

  • Maple
    a := proc(n) option remember; if n = 0 then 11550 else
    3*(3*n-1)*(3*n-2)/(n+4)^2*a(n-1) end if; end proc:
    seq(a(n), n = 0..20);

Formula

a(n) = (3^3)*(1*2*4*5*7*8*10*11)/((n+1)*(n+2)*(n+3)*(n+4))^2 * (3*n)!/n!^3.
a(n) = (1/3)*(1*2*4*5*7*8*10*11) * A006480(n+4)/((3*n + 1)*(3*n + 2)*(3*n + 4)* (3*n + 5)*(3*n + 7)*(3*n + 8)*(3*n + 10)*(3*n + 11)), where A006480(n) = (3*n)!/n!^3.
a(n) = (1/3)*27^(n+4)*binomial(10/3, n+4)*binomial(11/3, n+4).
a(n) = (1/7)*A348893(n)*A361039(n). It can be shown from this that a(n) is always an integer.
a(n) ~ sqrt(3)*3326400*(27^n)/(Pi*n^9).
P-recursive: (n + 4)^2*a(n) = 3*(3*n - 1)*(3*n - 2)*a(n-1) with a(0) = 11550.
The o.g.f. A(x) satisfies the differential equation x^2*(1 - 27*x)*A''(x) + x*(9 - 54*x)*A'(x) + (16 - 6*x)*A(x) - 184800 = 0, with A(0) = 11550 and A'(0) = 2772.

A361039 a(n) = 55440 * (3*n)!/((2*n)!*(n+4)!).

Original entry on oeis.org

2310, 1386, 2310, 5544, 16335, 55055, 204204, 813960, 3432198, 15142050, 69334650, 327523680, 1588667850, 7883530578, 39904290580, 205532444040, 1075067283906, 5701114384350, 30608320603770, 166169731127400, 911270544740325
Offset: 0

Views

Author

Peter Bala, Mar 04 2023

Keywords

Comments

Compare with the super ballot numbers A348893(n) = 840*(2*n)!/(n!*(n+4)!).

Crossrefs

Programs

  • Maple
    seq(  55440 * (3*n)!/((2*n)!*(n+4)!), n = 0..20);

Formula

a(n) = 2310*binomial(3*n,n) - 2057*binomial(3*n,n+1) + 627*binomial(3*n,n+2) - 102*binomial(3*n,n+3) + 7*binomial(3*n, n+4). Thus a(n) is an integer.
P-recursive: 2*(n + 4)*(2*n - 1) = 3*(3*n - 1)*(3*n - 2)*a(n-1) with a(0) = 2310.
a(n) ~ (27/4)^n * 27720*sqrt(3/Pi)/n^(9/2).
The o.g.f. satisfies the differential equation
x^2*(27*x - 4)*A''(x) + 2*x*(27*x - 9)*A'(x) + (6*x + 8)*A(x) - 18480 = 0, with A(0) = 2310 and A'(0) = 1386.

A348899 a(n) = 332640*4^n*Gamma(n + 1/2)/(sqrt(Pi)*Gamma(n + 7)); super ballot numbers, row 5 of A135573.

Original entry on oeis.org

462, 132, 99, 110, 154, 252, 462, 924, 1980, 4488, 10659, 26334, 67298, 177100, 478170, 1320660, 3721860, 10680120, 31150350, 92205036, 276615108, 840090328, 2580277436, 8007757560, 25090973688, 79319852304, 252832029219, 812127124158, 2627470107570, 8558045493228
Offset: 0

Views

Author

Peter Luschny, Nov 02 2021

Keywords

Crossrefs

Row 5 of array A135573.

Programs

  • Maple
    a := n -> 332640*4^n*GAMMA(n + 1/2)/(sqrt(Pi)*GAMMA(n + 7));
    seq(a(n), n = 0..29);
  • Mathematica
    a[n_] := 4^(n + 6) Hypergeometric2F1[13/2, 1/2 - n, 15/2, 1] / (13 Pi);
    Table[a[n], {n, 0, 29}]
    Array[332640*4^#*Gamma[# + 1/2]/(Sqrt[Pi]*Gamma[# + 7]) &, 30, 0] (* Michael De Vlieger, Nov 02 2021 *)

Formula

Let A[c, k](n) = c*4^n*Gamma(n + 1/2)/(sqrt(Pi)*Gamma(n + k)). Then
A[1, 1](n) = A000984(n).
A[3!, 3](n) = A007054(n).
A[5!*7, 5](n) = A348893(n).
A[7!*66, 7](n) = a(n).
A[c, k](n) ~ -c*2^(2*n - 1)*(k^2 - k - 2*n + 1/4)/(n^(k + 1/2)*sqrt(Pi)).
O.g.f.: ((2048*x^5 - 1686*x^4 + 765*x^3 - 178*x^2 + 21*x - 1)*sqrt(1 - 4*x) - 3496*x^5 + 2934*x^4 - 1083*x^3 + 218*x^2 - 23*x + 1)/(sqrt(1 - 4*x)*(1 + sqrt(1 - 4*x))*x^5).
E.g.f.: 1024*exp(2*x)*((-x^5 - 3/4*x^4 - 41/64*x^3 - 123/256*x^2 - 9/32*x - 15/128)*BesselI(1, 2*x) + BesselI(0, 2*x)*x*(x^4 + 1/2*x^3 + 27/64*x^2 + 9/32*x + 15/128))/x^5.
a(n) = Integral_{x=0..4} x^n*(4-x)^(11/2)/(2*Pi*sqrt(x)). This is the integral representation as the n-th moment of a positive function on [0, 4]. The representation is unique.
a(n) = 4^(n + 6)*hypergeom([13/2, 1/2 - n], [15/2], 1) / (13*Pi).
D-finite with recurrence (n+6)*a(n) +2*(-2*n+1)*a(n-1)=0. - R. J. Mathar, Jul 27 2022
From Peter Bala, Mar 11 2023: (Start)
a(n) = 332640*(2*n)!/(n!*(n + 6)!).
a(n) = Sum_{k = 0..5} (-1)^k*4^(5-k)*binomial(n,k)*Catalan(n+k), where Catalan(n) = A000108(n). Thus a(n) is an integer for all n.
a(n) is odd if n = 2^k - 6, k >= 3, otherwise a(n) is even. (End)
From Amiram Eldar, Mar 28 2023: (Start)
Sum_{n>=0} 1/a(n) = 101/3465 + 52*Pi/(6561*sqrt(3)).
Sum_{n>=0} (-1)^(n+1)/a(n) = 8573/54140625 + 104*log(phi)/(78125*sqrt(5)), where phi is the golden ratio (A001622). (End)

A361041 a(n) = 1680*(3*n)!/(n!*(2*n + 4)!).

Original entry on oeis.org

70, 14, 15, 28, 70, 210, 714, 2660, 10626, 44850, 197925, 906192, 4279240, 20746936, 102898110, 520543380, 2679559018, 14007652050, 74240555865, 398363958300, 2161524522150, 11847660496770, 65540249556600, 365634339159024
Offset: 0

Views

Author

Peter Bala, Mar 04 2023

Keywords

Comments

Compare with the super ballot numbers A348893(n) = 840*(2*n)!/(n!*(n+4)!).

Crossrefs

Programs

  • Maple
    seq( 1680*(3*n)!/(n!*(2*n + 4)!), n = 0..20);

Formula

a(n) = 70*binomial(3*n,2*n) - 196*binomial(3*n,2*n+1) + 141*binomial(3*n,2*n+2) - 65*binomial(3*n,2*n+3) + 14*binomial(3*n,2*n+4). Thus a(n) is an integer.
P-recursive: 2*(n + 2)*(2*n + 3)*a(n) = 3*(3*n - 1)*(3*n - 2)*a(n-1) with a(0) = 70.
a(n) ~ (27/4)^n * 105*sqrt(3/(4*Pi))/n^(9/2).
The o.g.f. A(x) satisfies the differential equation
x^2*(4 - 27*x^4)*A''(x) + 2*x*(9 - 27*x)*A'(x) + (12 - 6*x)*A(x) - 840 = 0, with A(0) = 70 and A'(0) = 14.
Showing 1-6 of 6 results.