A366593 G.f. A(x) satisfies A(x) = 1 + x^2*(1+x)^3*A(x)^4.

1, 0, 1, 3, 7, 25, 82, 278, 992, 3552, 12985, 48107, 179977, 680079, 2589915, 9931573, 38319117, 148640195, 579349123, 2267818509, 8911575579, 35141656433, 139018921717, 551557089103, 2194155973751, 8750097458849, 34973989188202, 140085055366350

Offset

0,4

Links

Table of n, a(n) for n=0..27.

Formula

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

Prog

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

Crossrefs

Cf. A366272, A366594, A366595.

Cf. A137954.

Sequence in context: A321606 A118398 A047974 * A148735 A148736 A148737

Adjacent sequences: A366590 A366591 A366592 * A366594 A366595 A366596

Keyword

nonn

Author

Seiichi Manyama, Oct 14 2023

Status

approved