A364523 G.f. satisfies A(x) = 1 + x*A(x) + x^6*A(x)^6.

1, 1, 1, 1, 1, 1, 2, 8, 29, 85, 211, 463, 931, 1795, 3550, 7736, 18929, 49505, 130000, 330430, 804271, 1885675, 4327555, 9929515, 23224435, 55907251, 138016906, 345107296, 862546231, 2136402451, 5231163232, 12697101118, 30723857209, 74569942745

Offset

0,7

Comments

Number of ordered trees with n edges and having nonleaf nodes of outdegrees 1 or 6. - Emanuele Munarini, Jul 11 2024

Links

Seiichi Manyama, Table of n, a(n) for n = 0..1000

Formula

a(n) = Sum_{k=0..floor(n/6)} binomial(n,6*k) * binomial(6*k,k) / (5*k+1).

Prog

(PARI) a(n) = sum(k=0, n\6, binomial(n, 6*k)*binomial(6*k, k)/(5*k+1));

Crossrefs

Cf. A001006, A071879, A127902, A364522.

Cf. A349312, A364472.

Sequence in context: A241627 A293169 A306847 * A107025 A212385 A333882

Adjacent sequences: A364520 A364521 A364522 * A364524 A364525 A364526

Keyword

nonn

Author

Seiichi Manyama, Jul 27 2023

Status

approved