A364552 G.f. satisfies A(x) = 1 + x*A(x) + x^4*A(x)^3.

1, 1, 1, 1, 2, 5, 11, 21, 39, 78, 169, 373, 808, 1727, 3719, 8153, 18100, 40315, 89770, 200250, 448755, 1010685, 2284295, 5173961, 11740697, 26699780, 60863291, 139045991, 318247190, 729572315, 1675085099, 3851795549, 8869990949, 20453679944, 47223844863

Offset

0,5

Links

Table of n, a(n) for n=0..34.

Formula

a(n) = Sum_{k=0..floor(n/4)} binomial(n-k,3*k) * binomial(3*k,k) / (2*k+1).

Prog

(PARI) a(n) = sum(k=0, n\4, binomial(n-k, 3*k)*binomial(3*k, k)/(2*k+1));

Crossrefs

Cf. A000108, A071879, A346626.

Cf. A023426, A063019, A127902.

Sequence in context: A023548 A144700 A000785 * A369525 A364591 A049936

Adjacent sequences: A364549 A364550 A364551 * A364553 A364554 A364555

Keyword

nonn,easy

Author

Seiichi Manyama, Jul 28 2023

Status

approved