A340813 Number of oriented polygonal 2-trees with n oriented quadrilaterals.

1, 1, 1, 3, 11, 49, 252, 1406, 8405, 52348, 337029, 2225333, 15002763, 102896407, 716106077, 5046649182, 35956186581, 258649116963, 1876462272125, 13717081730294, 100957850485311, 747631534534529, 5567459642741752, 41671027665802639, 313351688709886964, 2366390596263188755

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.

Prog

(PARI) C(25, 4) \\ See A340812 for C(n, k).

Crossrefs

Column k=4 of A340812.

Sequence in context: A074528 A246985 A326521 * A004211 A180869 A357836

Adjacent sequences: A340810 A340811 A340812 * A340814 A340815 A340816

Keyword

nonn

Author

Andrew Howroyd, Feb 02 2021

Status

approved