A371494 G.f. A(x) satisfies A(x) = 1 / (1 - x*A(x) / (1+x))^2.

1, 2, 5, 18, 72, 310, 1399, 6532, 31287, 152876, 759034, 3818410, 19420713, 99697784, 515909606, 2688267462, 14093211259, 74281217492, 393389969722, 2092312452404, 11171325560120, 59854910468196, 321717833732186, 1734250394445622, 9373581927760595

Offset

0,2

Links

Table of n, a(n) for n=0..24.

Formula

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

Prog

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

Crossrefs

Cf. A001006, A371495, A371496.

Cf. A006013.

Sequence in context: A141494 A189843 A045612 * A103940 A162543 A039744

Adjacent sequences: A371491 A371492 A371493 * A371495 A371496 A371497

Keyword

nonn

Author

Seiichi Manyama, Mar 25 2024

Status

approved