A111757 Number of bipartite 2-connected outerplanar graphs on n unlabeled nodes.

0, 1, 0, 1, 0, 2, 0, 4, 0, 13, 0, 48, 0, 238, 0, 1325, 0, 8297, 0, 54519, 0, 373363, 0, 2621872, 0, 18797682, 0, 136969519, 0, 1011903735, 0, 7564219361, 0, 57129086391, 0, 435394899361, 0, 3345082819597, 0, 25885718422329, 0, 201619294539406, 0, 1579629974876090

Offset

1,6

Comments

Also the number of bipartite (unlabeled) dissections of a polygon.

Links

Table of n, a(n) for n=1..44.

M. Bordirsky, É. Fusy, M. Kang and S. Vigerske, Enumeration of Unlabeled Outerplanar Graphs, 2005

S. Vigerske, Asymptotic enumeration of unlabeled outerplanar graphs, Diploma thesis, Humboldt University Berlin, 2005

S. Vigerske, Homepage

Formula

Generating function and cycle index sum known, see Vigerske.

Prog

(PARI) \\ See A295419 for DissectionsModDihedral.
{my(N=50); DissectionsModDihedral(vector(N, n, n%2==0)) + vector(N, n, n==2)} \\ Andrew Howroyd, Feb 12 2021

Crossrefs

Even bisection gives A290722.

Cf. A001004, A111758, A111759, A295419.

Sequence in context: A056946 A225740 A349479 * A286122 A286776 A265829

Adjacent sequences: A111754 A111755 A111756 * A111758 A111759 A111760

Keyword

nonn

Author

Stefan Vigerske, Nov 21 2005

Extensions

Terms a(21) and beyond from Andrew Howroyd, Feb 12 2021

Status

approved