OFFSET
0,4
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..10000
FORMULA
Euler transform of period 30 sequence [ 0, 1, 2, 1, 2, 0, 0, 1, 2, 0, 0, 0, 0, 1, 4, 1, 0, 0, 0, 0, 2, 1, 0, 0, 2, 1, 2, 1, 0, 0, ...].
a(n) = A132968(2*n).
EXAMPLE
G.f. = 1 + x^2 + 2*x^3 + 2*x^4 + 4*x^5 + 5*x^6 + 6*x^7 + 11*x^8 + 14*x^9 + 17*x^10 + ...
MATHEMATICA
a[ n_] := SeriesCoefficient[ QPochhammer[ q^6]^3 QPochhammer[ q^10]^3 / (QPochhammer[ q^2] QPochhammer[ q^3]^2 QPochhammer[ q^5]^2 QPochhammer[ q^30]), {q, 0, n}];
PROG
(PARI) {a(n) = my(A); if( n<0, 0, A = x * O(x^n); polcoeff( eta(x^6 + A)^3 * eta(x^10 + A)^3 / (eta(x^2 + A) * eta(x^3 + A)^2 * eta(x^5 + A)^2 * eta(x^30 + A)), n))};
CROSSREFS
KEYWORD
nonn
AUTHOR
Michael Somos, Nov 04 2015
STATUS
approved