OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..2500
FORMULA
EXAMPLE
G.f. = 1 + 2*x + 5*x^2 + 10*x^3 + 20*x^4 + 36*x^5 + 63*x^6 + 106*x^7 + ...
MATHEMATICA
a[ n_] := SeriesCoefficient[ (QPochhammer[ q^6] QPochhammer[ q^10] / (QPochhammer[ q] QPochhammer[ q^15]))^2, {q, 0, n}];
PROG
(PARI) {a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( (eta(x^6 + A) * eta(x^10 + A) / (eta(x + A) * eta(x^15 + A)))^2, n))};
(PARI) q='q+O('q^99); Vec((eta(q^6)*eta(q^10)/(eta(q)*eta(q^15)))^2) \\ Altug Alkan, Jul 31 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Michael Somos, Oct 15 2015
STATUS
approved