A094637 Number of unlabeled hexagonal 2-trees with n hexagons.

1, 1, 1, 4, 16, 103, 799, 7286, 71094, 729974, 7743818, 84307887, 937002302, 10595117272, 121568251909, 1412555701804, 16594126114458, 196829590326284, 2354703777373055, 28385225424840078, 344524656398655124, 4207569734885041198, 51674558137433627724

Offset

0,4

Links

Andrew Howroyd, Table of n, a(n) for n = 0..200

G. Labelle, C. Lamathe and P. Leroux, Labeled and unlabeled enumeration of k-gonal 2-trees, arXiv:math/0312424 [math.CO], Dec 23 2003.

Crossrefs

Column k=6 of A340811.

Cf. A054581.

Sequence in context: A370529 A245155 A334750 * A332783 A332773 A203716

Adjacent sequences: A094634 A094635 A094636 * A094638 A094639 A094640

Keyword

nonn

Author

Vladeta Jovovic, Jun 06 2004

Extensions

Terms a(21) and beyond from Andrew Howroyd, Feb 02 2021

Status

approved