OFFSET
0,2
FORMULA
G.f.: Product_{n>=1} (1-q^n)^(2*A288851(n)/3).
a(n) ~ c * exp(2*Pi*n) / n^(5/3), where c = -3^(1/3) * Gamma(1/4)^(32/3) / (128 * 2^(2/3) * Pi^8 * Gamma(1/3)) = -0.258650618394676269905172499217587002338... - Vaclav Kotesovec, Jul 08 2017, updated Mar 05 2018
MATHEMATICA
nmax = 20; CoefficientList[Series[(1 - 504*Sum[DivisorSigma[5, k]*x^k, {k, 1, nmax}])^(2/3), {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 08 2017 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Jul 03 2017
STATUS
approved