OFFSET
0,5
FORMULA
G.f.: Product_{k>0} (1-x^(7*k))^3 * ((1-x^(7*k-2)) * (1-x^(7*k-5)))^2 / (1-x^k).
G.f.: Sum_{k in Z} x^(4*k) / (1 - x^(7*k+1)).
PROG
(PARI) my(N=110, x='x+O('x^N)); Vec(sum(k=-N, N, x^k/(1-x^(7*k+4))))
(PARI) my(N=110, x='x+O('x^N)); Vec(prod(k=1, N, (1-x^(7*k))^3*((1-x^(7*k-2))*(1-x^(7*k-5)))^2/(1-x^k)))
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Aug 01 2024
STATUS
approved