OFFSET
0,34
COMMENTS
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
Michael Somos, Introduction to Ramanujan theta functions
Eric Weisstein's World of Mathematics, Ramanujan Theta Functions
FORMULA
EXAMPLE
G.f. = 1 + x + x^5 + x^8 + x^12 + x^13 + x^16 + x^17 + x^20 + x^21 + x^28 + ...
G.f. = q^11 + q^17 + q^41 + q^59 + q^83 + q^89 + q^107 + q^113 + q^131 + ...
MATHEMATICA
a[ n_] := SeriesCoefficient[ QPochhammer[ -x, x^2] EllipticTheta[ 2, 0, x^6] EllipticTheta[ 2, Pi/4, x^(3/2)] / (2^(3/2) x^(15/8)), {x, 0, n}];
PROG
(PARI) {a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x^2 + A)^2 * eta(x^3 + A) * eta(x^24 + A)^2 / (eta(x + A) * eta(x^4 + A) * eta(x^6 + A)), n))};
CROSSREFS
KEYWORD
nonn
AUTHOR
Michael Somos, Apr 21 2015
STATUS
approved