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.

A255052 G.f.: Product_{j>=1} 1/(1-x^j)^binomial(j+4,4).

Original entry on oeis.org

1, 5, 30, 145, 660, 2777, 11160, 42805, 158490, 568050, 1980607, 6735380, 22402610, 73022755, 233692345, 735350970, 2278153310, 6956560935, 20958613740, 62354061740, 183332498533, 533074229590, 1533842417185, 4369816273820, 12332669124455, 34495668855729
Offset: 0

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Author

Vaclav Kotesovec, Mar 08 2015

Keywords

Comments

In general, if g.f. = product_{j>=1} 1/(1-x^j)^binomial(j+k-1,k-1), k>=1, then log(a(n)) ~ (1+1/k) * k^(1/(k+1)) * Zeta(k+1)^(1/(k+1)) * n^(k/(k+1)).

Crossrefs

Column k=5 of A075196.

Programs

  • Maple
    with(numtheory):
    a:= proc(n) option remember; local d, j; `if`(n=0, 1,
          add(add(d*binomial(d+4, 4), d=divisors(j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..50);  # after Alois P. Heinz
  • Mathematica
    nmax=50; CoefficientList[Series[Product[1/(1-x^j)^Binomial[j+4,4],{j,1,nmax}],{x,0,nmax}],x]

Formula

G.f.: Product_{j>=1} 1/(1-x^j)^C(j+4,4).
a(n) ~ Pi^(49/288) * exp(25/144 - 105*Zeta(3) / (8*Pi^2) + 5*Zeta'(-3)/12 + 29299*Zeta(5) / (128*Pi^4) + 2480625 * Zeta(3) * Zeta(5)^2 / (2*Pi^12) - 72930375 * Zeta(5)^3 / (2*Pi^14) + 1063324867500 * Zeta(5)^5 / Pi^24 + 41 * 7^(1/6) * Pi * n^(1/6) / (768*3^(1/2)) - 2625 * 3^(1/2) * 7^(1/6) * Zeta(3) * Zeta(5) * n^(1/6) / (2*Pi^7) + 540225 * 3^(1/2) * 7^(1/6) * Zeta(5)^2 * n^(1/6) / (16*Pi^9) - 4740474375 * 3^(1/2) * 7^(1/6) * Zeta(5)^4 * n^(1/6) / (4*Pi^19) + 25 * 7^(1/3) * Zeta(3) * n^(1/3) / (4*Pi^2) - 735 * 7^(1/3) * Zeta(5) * n^(1/3) / (8*Pi^4) + 3969000 * 7^(1/3) * Zeta(5)^3 * n^(1/3) / Pi^14 + 7^(3/2) * Pi * n^(1/2) / (3^(3/2)*8) - 4725 * 21^(1/2) * Zeta(5)^2 * n^(1/2) / Pi^9 + 45 * 7^(2/3) * Zeta(5) * n^(2/3) / (2*Pi^4) + 2 * 3^(1/2) * Pi * n^(5/6) / (5 * 7^(1/6))) / (A^(25/12) * 2^(3/2) * 3^(625/576) * 7^(337/1728) * n^(1201/1728)), where A = A074962 = 1.2824271291... is the Glaisher-Kinkelin constant, Zeta(3) = A002117 = 1.202056903..., Zeta(5) = A013663 = 1.036927755... and Zeta'(-3) = ((gamma + log(2*Pi) - 11/6)/30 - 3*Zeta'(4)/Pi^4)/4 = 0.0053785763577743... .