A263136 Expansion of Product_{k>=1} 1/(1-x^(4*k-1))^k.
1, 0, 0, 1, 0, 0, 1, 2, 0, 1, 2, 3, 1, 2, 6, 5, 2, 6, 11, 7, 6, 15, 21, 12, 15, 30, 34, 22, 35, 58, 59, 43, 70, 108, 95, 85, 142, 187, 161, 167, 263, 318, 274, 318, 480, 534, 471, 595, 836, 879, 819, 1081, 1433, 1442, 1429, 1915, 2391, 2365, 2483, 3314, 3947
Offset: 0
Keywords
Links
- Vaclav Kotesovec, Table of n, a(n) for n = 0..10000
- Vaclav Kotesovec, A method of finding the asymptotics of q-series based on the convolution of generating functions, arXiv:1509.08708 [math.CO], Sep 30 2015
Programs
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Maple
with(numtheory): a:= proc(n) option remember; `if`(n=0, 1, add(add(d* `if`(irem(d+4, 4, 'r')=3, r, 0), d=divisors(j))*a(n-j), j=1..n)/n) end: seq(a(n), n=0..100); # after Alois P. Heinz -
Mathematica
nmax = 100; CoefficientList[Series[Product[1/(1-x^(4k-1))^k, {k, 1, nmax}], {x, 0, nmax}], x] nmax = 100; CoefficientList[Series[E^Sum[1/j*x^(3*j)/(1 - x^(4*j))^2, {j, 1, nmax}], {x, 0, nmax}], x]
Formula
G.f.: exp(Sum_{j>=1} 1/j*x^(3*j)/(1 - x^(4*j))^2).
a(n) ~ Zeta(3)^(53/288) * exp(d41 - Pi^4/(6912*Zeta(3)) + Pi^2 * n^(1/3) / (48*Zeta(3)^(1/3)) + 3 * Zeta(3)^(1/3) * n^(2/3)/4) / (sqrt(3*Pi) * 2^(101/96) * n^(197/288)), where d41 = A263176 = Integral_{x=0..infinity} exp(-3*x)/(x*(1 - exp(-4*x))^2) - 1/(16*x^3) - 1/(16*x^2) + 5/(96*x*exp(x)) = -0.158924147180165035059952001737321408554746599955833696821824808027... .