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 1-5 of 5 results.

A001421 a(n) = (6*n)!/((n!)^3*(3*n)!).

Original entry on oeis.org

1, 120, 83160, 81681600, 93699005400, 117386113965120, 155667030019300800, 214804163196079142400, 305240072216678400087000, 443655767845074392936328000, 656486312795713480715743268160, 985646873056680684690542988249600, 1497786250388951255453847206769124800
Offset: 0

Views

Author

N. J. A. Sloane, Glenn K Painter (KUPK78A(AT)prodigy.com)

Keywords

Comments

Self-convolution of A092870, where A092870(n) = (12^n/n!^2) * Product_{k=0..n-1} (12k+1)*(12k+5). - Paul D. Hanna, Jan 25 2011

Examples

			G.f.: A(x) = 1 + 120*x + 83160*x^2 + 81681600*x^3 + ...
A(x)^(1/2) = 1 + 60*x + 39780*x^2 + 38454000*x^3 + ... + A092870(n)*x^n + ...
		

Crossrefs

Programs

  • Magma
    [Factorial(6*n)/(Factorial(n)^3*Factorial(3*n)): n in [0..15]]; // Vincenzo Librandi, Oct 26 2011
  • Maple
    f := n->(6*n)!/( (n!)^3*(3*n)!);
  • Mathematica
    Factorial[6 n]/(Factorial[3n] Factorial[n]^3) (* Jacob Lewis (jacobml(AT)uw.edu), Jul 28 2009 *)
    a[ n_] := SeriesCoefficient[ HypergeometricPFQ[ {1/6, 1/2, 5/6}, {1, 1}, 1728 x], {x, 0, n}] (* Michael Somos, Jul 11 2011 *)
  • PARI
    {a(n)=(2*n)!/n!^2*(12^n/n!^2)*prod(k=0, n-1, (6*k+1)*(6*k+5))} \\ Paul D. Hanna, Jan 25 2011
    

Formula

O.g.f.: Hypergeometric2F1(5/12, 1/12; 1; 1728x)^2. - Jacob Lewis (jacobml(AT)uw.edu), Jul 28 2009
a(n) = binomial(2n,n) * (12^n/n!^2) * Product_{k=0..n-1} (6k+1)*(6k+5). - Paul D. Hanna, Jan 25 2011
G.f.: F(1/6, 1/2, 5/6; 1, 1; 1728*x), a hypergeometric series. - Michael Somos, Feb 28 2011
0 = y^3*z^3 - 360*y^4*z^2 + 43200*y^5*z - 1728000*y^6 - 16632*x*y^2*z^3 + 7691328*x*y^3*z^2 - 1738520064*x*y^4*z + 176027074560*x*y^5 + 92207808*x^2*y*z^3 - 69176553984*x^2*y^2*z^2 + 23624298528768*x^2*y^3*z - 2853152143441920*x^2*y^4 - 170400029184*x^3*z^3 + 224945232150528*x^3*y*z^2 - 92759146352345088*x^3*y^2*z + 11686511179538104320*x^3*y^3 where x = a(n), y = a(n+1), z = a(n+2) for all n in z. - Michael Somos, Sep 21 2014
a(n) ~ 2^(6*n - 1) * 3^(3*n) / (Pi^(3/2) * n^(3/2)). - Vaclav Kotesovec, Apr 07 2018
From Peter Bala, Feb 14 2020: (Start)
a(n) = binomial(6*n,n)*binomial(5*n,n)*binomial(4*n,n) = ( [x^n](1 + x)^(6*n) ) * ( [x^n](1 + x)^(5*n) ) * ( [x^n](1 + x)^(4*n) ) = [x^n](F(x)^(120*n)), where F(x) = 1 + x + 227*x^2 + 123980*x^3 + 92940839*x^4 + 82527556542*x^5 + 81459995686401*x^6 + ...
appears to have integer coefficients. For similar results see A008979.
a(m*p^k) == a(m*p^(k-1)) ( mod p^(3*k) ) for prime p >= 5 and positive integers m and k - apply Mestrovic, equation 39, p. 12.
a(n) = [(x*y*z)^n] (1 + x + y + z)^(6*n). (End)
a(n) = (8^n/n!^3)*Product_{k = 0..3*n-1} (2*k + 1). - Peter Bala, Feb 26 2023
a(n) = 24*(6*n - 1)*(2*n - 1)*(6*n - 5)*a(n-1)/n^3. - Neven Sajko, Jul 19 2023
From Karol A. Penson, Jan 21 2025: (Start)
a(n) = Integral_{x=0..1728} x^n*W(x), with W(x) = W1(x) + W2(x) + W3(x), where
W1(x) = hypergeometric([1/6, 1/6, 1/6], [1/3, 2/3], x/1728)/(6*sqrt(Pi)*x^(5/6)*Gamma(5/6)^3),
W2(x) = - hypergeometric([1/2, 1/2, 1/2], [2/3, 4/3], x/1728)/(24*Pi^2*sqrt(x)), and
W3(x) = hypergeometric([5/6, 5/6, 5/6], [4/3, 5/3], x/1728)*Gamma(5/6)^3/(1536*Pi^(7/2)*x^(1/6)). This integral representation is unique as W(x) is the solution of the Hausdorff power moment problem on x = (0, 1728). Using only the definition of a(n), W(x) can be proven to be positive. W(x) is singular at x = 0, with singularity x^(-1/6), and for x > 0 is monotonically decreasing to zero at x = 1728. (End)

A145492 Coefficients of certain power series associated with Atkin polynomials (see Kaneko-Zagier reference for precise definition).

Original entry on oeis.org

1, 450, 394680, 429557700, 522037315800, 678696698599920, 923563866149496000, 1298893924326291064200, 1872892788786285985719000, 2753834730409783196154778800, 4113309164116707723917886096960
Offset: 0

Views

Author

N. J. A. Sloane, Feb 28 2009

Keywords

Crossrefs

Programs

  • PARI
    {a(n) = (8*n+7)*(6*n+1)!/(7*(3*n)!*n!*(n+1)!^2)} \\ Seiichi Manyama, Aug 20 2018

Formula

a(n) = (8*n+7)*(6*n+1)!/(7*(3*n)!*n!*(n+1)!^2). - Seiichi Manyama, Aug 20 2018

Extensions

More terms from Vladeta Jovovic, Feb 28 2009

A145494 Coefficients of certain power series associated with Atkin polynomials (see Kaneko-Zagier reference for precise definition).

Original entry on oeis.org

1, 1335, 1757970, 2386445040, 3336565609080, 4780478992153590, 6986981484124227300, 10379857332015914783040, 15630336095483779833585240, 23805745537435619756724715080, 36609525021962109091946530420080
Offset: 0

Views

Author

N. J. A. Sloane, Feb 28 2009

Keywords

Crossrefs

Formula

a(n) = (A145493(n+1) - A145492(n+1))/494. - Seiichi Manyama, Aug 18 2018

Extensions

More terms from Vladeta Jovovic, Feb 28 2009

A318200 Expansion of Hypergeometric function F(17/12, 13/12; 3; 1728*x) in powers of x.

Original entry on oeis.org

1, 884, 961350, 1166694360, 1514952626460, 2059469884770480, 2894070055573717020, 4170217137221937001200, 6128342594004497520113460, 9149429785497381327907574160, 13838512550564789258460205917000, 21159569553888757349236649959188000, 32653750015126185895018415883446910000
Offset: 0

Views

Author

Seiichi Manyama, Aug 21 2018

Keywords

Comments

A145493 is the convolution of A092870 and this sequence.

Crossrefs

F([b/2]+5/12, [(b+1)/2]+1/12; b+1; 1728*x): A092870 (b=0), A318174 (b=1), this sequence (b=2), A318201 (b=3).
Cf. A145493.

Programs

  • PARI
    {a(n) = 2*12^n/(n!*(n+2)!)*prod(k=0, n-1, (12*k+17)*(12*k+13))}

Formula

a(n) = (2*12^n/(n!*(n+2)!)) * Product_{k=0..n-1} (12k+17)*(12k+13).
a(n) = 2*(12*n+1)*(12*n+5)*A092870(n)/(5*(n+1)*(n+2)).
a(n) ~ 2^(6*n + 5) * 3^(3*n + 2) / (5 * Gamma(1/12) * Gamma(5/12) * n^(3/2)). - Vaclav Kotesovec, Aug 21 2018

A145495 Coefficients of certain power series associated with Atkin polynomials (see Kaneko-Zagier reference for precise definition).

Original entry on oeis.org

1, 84, 27720, 13693680, 5354228880, 2489716429200, 1010824870255200, 459492105307435200, 189737418627305920800, 85223723866764909426000, 35532611270849849570013600, 15842376246977818384652245440, 6646596943618421076833646609600, 2948532659526725719238433845966400
Offset: 0

Views

Author

N. J. A. Sloane, Feb 28 2009

Keywords

Examples

			From _Seiichi Manyama_, Aug 19 2018: (Start)
Phi_0(t)/1       = 1 + 120*t +  83160*t^2 + ... (See A001421).
Phi_1(t)/(84*t)  = 1 + 450*t + 394680*t^2 + ... (See A145492).
Phi_2(t)/(27720*t^2)
= (1 + 450*t + 394680*t^2 + ... - (1 + 120*t +  83160*t^2 + ... ))/(330*t)
= 1 + 944*t + 1054170*t^2 + ... (See A145493).
Phi_3(t)/(13693680*t^3)
= (1 + 944*t + 1054170*t^2 + ... - (1 + 450*t + 394680*t^2 + ... ))/(494*t)
= 1 + 1335*t + 1757970*t^2 + ... (See A145494).
Phi_4(t)/(5354228880*t^4)
= (1 + 1335*t + 1757970*t^2 + ... - (1 + 944*t + 1054170*t^2 + ... ))/(391*t)
= 1 + 1800*t + 2783760*t^2 + ... .
Phi_5(t)/(2489716429200*t^5)
= (1 + 1800*t + 2783760*t^2 + ... - (1 + 1335*t + 1757970*t^2 + ... ))/(465*t)
= 1 + 2206*t + 3863952*t^2 + ... .
Phi_6(t)/(1010824870255200*t^6)
= (1 + 2206*t + 3863952*t^2 + ... - (1 + 1800*t + 2783760*t^2 + ... ))/(406*t)
= 1 + 18624/7*t + 36827541/7*t^2 + ... .
Phi_7(t)/(459492105307435200*t^6)
= (1 + 18624/7*t + 36827541/7*t^2 + ... - (1 + 2206*t + 3863952*t^2 + ... ))/((3182/7)*t)
= 1 + (6147/2)*t + 6715687*t^2 + ... . (End)
		

Crossrefs

Formula

From Seiichi Manyama, Aug 19 2018: (Start)
a(n) = (6*n+1)!/((n-1)!*(2*n)!*(3*n)!*(6*n+(-1)^n)) for n > 0.
a(n) = 12*(6*n-6+(-1)^(n-1))*(6*n+(-1)^(n-1))*a(n-1)/((n-1)*n) for n > 1. (End)

Extensions

More terms from Seiichi Manyama, Aug 19 2018
Showing 1-5 of 5 results.