A367041 G.f. satisfies A(x) = 1 + x^2 + x*A(x)^4.

1, 1, 5, 26, 168, 1195, 8988, 70318, 566388, 4665221, 39113732, 332691758, 2863778072, 24900264326, 218372530380, 1929363592870, 17157018725000, 153442147343648, 1379250344938676, 12453816724761706, 112907775890596400, 1027394297869071687

Offset

0,3

Links

Table of n, a(n) for n=0..21.

Formula

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

Prog

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

Crossrefs

Cf. A176697, A367040.

Cf. A365178, A365180, A365181, A365182, A365183, A367048, A367049, A367050.

Sequence in context: A367285 A349882 A209672 * A057793 A090226 A355672

Adjacent sequences: A367038 A367039 A367040 * A367042 A367043 A367044

Keyword

nonn

Author

Seiichi Manyama, Nov 03 2023

Status

approved