A112948 Number of unrooted 3-regular planar maps with 2n vertices, up to orientation-preserving isomorphisms.

2, 6, 26, 191, 1904, 22078, 282388, 3848001, 54953996, 814302292

Offset: 1

Author

Valery A. Liskovets, Oct 10 2005

Keywords

• nonn

Comments

A 3-regular map is a regular map with valency 3.

Examples

			There exist 2 planar maps with two 3-valent vertices: a map with three parallel edges and a map with one loop in each vertex and a link connecting the vertices. Therefore a(1)=2.
		

Links

• Z. C. Gao, V. A. Liskovets and N. C. Wormald, Enumeration of unrooted odd-valent regular planar maps, Preprint, 2005.
• Mark van Hoeij, Vijay Jung Kunwar, Classifying (near)-Belyi maps with Five Exceptional Points, arXiv preprint arXiv:1604.08158, 2016. Also in Indagationes Mathematicae (2019) Vol. 30, No. 1, 136-156.
• Riccardo Murri, Fatgraph algorithms and the homology of the Kontsevich complex, arXiv preprint arXiv:1202.1820, 2012.

Crossrefs

Cf. A112944, A112945, A112949 (5-regular), A005470.

3-regular maps on the torus: A292408.