OFFSET
1,2
FORMULA
a(n) ~ exp(2*Pi*sqrt(n/21)) * 3^(1/28) * Gamma(1/7) * Gamma(2/7) / (4 * 7^(15/28) * Pi^(11/7) * n^(13/28)). - Vaclav Kotesovec, Aug 27 2015
MATHEMATICA
nmax = 100; Rest[CoefficientList[Series[Product[1/((1 - x^(7k+1))*(1 - x^(7k+2))), {k, 0, nmax}], {x, 0, nmax}], x]] (* Vaclav Kotesovec, Aug 27 2015 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved