OFFSET
0,8
FORMULA
G.f.: 1/sqrt((1 - x^2 + x^5)^2 - 4*x^5) = 1/sqrt((1 + x^2 - x^5)^2 - 4*x^2).
PROG
(PARI) my(N=50, x='x+O('x^N)); Vec(1/sqrt((1-x^2-x^5)^2-4*x^7))
(PARI) a(n) = sum(k=0, n\5, ((n-3*k)%2==0)*binomial((n-3*k)/2, k)^2);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 04 2024
STATUS
approved