OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..423
FORMULA
G.f.: Product_{n>=1} (1-q^n)^(-A110163(n)/2).
a(n) ~ (-1)^n * c * exp(Pi*sqrt(3)*n) / sqrt(n), where c = 3^(7/2) * Gamma(2/3)^9 / (2^(9/2) * Pi^(7/2)) = 0.5756695813762774104492155417156662666189119445257965... - Vaclav Kotesovec, Jul 09 2017, updated Mar 05 2018
MATHEMATICA
nmax = 20; CoefficientList[Series[(1 + 240*Sum[DivisorSigma[3, k]*x^k, {k, 1, nmax}])^(-1/2), {x, 0, nmax}], x] (* Vaclav Kotesovec, Jul 09 2017 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Jul 08 2017
STATUS
approved