A364522 G.f. satisfies A(x) = 1 + x*A(x) + x^5*A(x)^5.

1, 1, 1, 1, 1, 2, 7, 22, 57, 127, 258, 518, 1123, 2718, 7008, 18054, 44969, 108189, 255919, 609179, 1482210, 3689155, 9294440, 23419705, 58639835, 145948111, 362721386, 904673836, 2270287636, 5729191861, 14502873988, 36735974548, 93001413353, 235372519273

Offset

0,6

Comments

Number of ordered trees with n edges and having nonleaf nodes of outdegrees 1 or 5. - 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/5)} binomial(n,5*k) * binomial(5*k,k) / (4*k+1).

Prog

(PARI) a(n) = sum(k=0, n\5, binomial(n, 5*k)*binomial(5*k, k)/(4*k+1));

Crossrefs

Cf. A001006, A071879, A127902, A364523.

Cf. A182454, A349311.

Sequence in context: A365798 A139398 A365736 * A226910 A275423 A099131

Adjacent sequences: A364519 A364520 A364521 * A364523 A364524 A364525

Keyword

nonn,changed

Author

Seiichi Manyama, Jul 27 2023

Status

approved