OFFSET
1,11
FORMULA
a(n) ~ exp(2*Pi*sqrt(n/21)) * 7^(1/28) * Gamma(4/7) / (4 * 3^(15/28) * Pi^(3/7) * n^(29/28)). - Vaclav Kotesovec, Aug 27 2015
MATHEMATICA
nmax = 100; Rest[CoefficientList[Series[Product[1/((1 - x^(7k+7))*(1 - x^(7k+4))), {k, 0, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Aug 27 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved