OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..1000
Wikipedia, Ramanujan's congruences
FORMULA
G.f.: Product_{n>=1} (1 - x^(7*n))^7/(1 - x^n)^8.
a(n) ~ exp(Pi*sqrt(98*n/21)) / (1372*sqrt(3)*n). - Vaclav Kotesovec, Nov 10 2017
EXAMPLE
G.f.: 1 + 8*x + 44*x^2 + 192*x^3 + 726*x^4 + 2464*x^5 + 7704*x^6 + ...
MATHEMATICA
nmax = 20; CoefficientList[Series[Product[(1 - x^(7*k))^7 /(1 - x^k)^8 , {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Nov 10 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Nov 06 2016
STATUS
approved