OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..1000
G. N. Watson, Ramanujans Vermutung über Zerfällungsanzahlen, J. Reine Angew. Math. (Crelle), 179 (1938), 97-128.
FORMULA
See Maple code in A160525 for formula.
G.f.: Product_{n>=1} (1 - x^(7*n))^4/(1 - x^n)^5. - Seiichi Manyama, Nov 06 2016
a(n) ~ exp(Pi*sqrt(62*n/21)) * sqrt(31) / (4*sqrt(3) * 7^(5/2) * n). - Vaclav Kotesovec, Nov 10 2017
EXAMPLE
G.f. = 1 + 5*x + 20*x^2 + 65*x^3 + 190*x^4 + 506*x^5 + 1265*x^6 + ...
G.f. = q^23 + 5*q^47 + 20*q^71 + 65*q^95 + 190*q^119 + 506*q^143 + 1265*q^167 + ...
MATHEMATICA
nmax = 50; CoefficientList[Series[Product[(1 - x^(7*k))^4 /(1 - x^k)^5, {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Nov 10 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 13 2009
STATUS
approved