A094651 Number of unlabeled heptagonal 2-trees with n heptagons.

1, 1, 1, 4, 20, 158, 1539, 16970, 199879, 2460350, 31266165, 407461893, 5420228329, 73352481577, 1007312969202, 14008437540003, 196963172193733, 2796235114720116, 40038505601111596, 577693117173844307, 8392528734991449808, 122680472402091278920, 1803416089912665770579

Offset: 0

Author

Vladeta Jovovic, Jun 06 2004

Keywords

• nonn

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=7 of A340811.

Cf. A054581.

Extensions

Terms a(20) and beyond from Andrew Howroyd, Feb 02 2021