login
A376724
Expansion of 1/((1 - x^3 - x^4)^2 - 4*x^7).
5
1, 0, 0, 2, 2, 0, 3, 10, 3, 4, 28, 28, 9, 60, 126, 66, 115, 396, 403, 292, 1007, 1724, 1281, 2366, 5736, 6128, 6468, 16202, 24888, 23664, 43055, 85158, 97156, 124044, 257474, 374538, 421785, 740324, 1294129, 1577756, 2217676, 4085272, 5813587, 7319572, 12370630
OFFSET
0,4
FORMULA
a(n) = 2*a(n-3) + 2*a(n-4) - a(n-6) + 2*a(n-7) - a(n-8).
a(n) = (1/2) * Sum_{k=0..floor(n/3)} binomial(2*k+2,2*n-6*k+1).
PROG
(PARI) my(N=50, x='x+O('x^N)); Vec(1/((1-x^3-x^4)^2-4*x^7))
(PARI) a(n) = sum(k=0, n\3, binomial(2*k+2, 2*n-6*k+1))/2;
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 02 2024
STATUS
approved