OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..425
FORMULA
G.f.: Product_{n>=1} (1-q^n)^(3*A110163(n)/4).
a(n) ~ (-1)^(n+1) * c * exp(Pi*sqrt(3)*n) / n^(7/4), where c = 3^(5/2) * Gamma(1/3)^(27/2) / (256 * 2^(3/4) * Pi^9 * Gamma(1/4)) = 0.2007048471908800363193160136812560289856774734680572658944418664975... - Vaclav Kotesovec, Jul 08 2017, updated Mar 05 2018
MATHEMATICA
nmax = 20; CoefficientList[Series[(1 + 240*Sum[DivisorSigma[3, k]*x^k, {k, 1, nmax}])^(3/4), {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 08 2017 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Jul 02 2017
STATUS
approved