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A112948 Number of unrooted 3-regular planar maps with 2n vertices, up to orientation-preserving isomorphisms. 1
2, 6, 26, 191, 1904, 22078, 282388, 3848001, 54953996, 814302292 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
A 3-regular map is a regular map with valency 3.
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.
EXAMPLE
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.
CROSSREFS
Cf. A112944, A112945, A112949 (5-regular), A005470.
3-regular maps on the torus: A292408.
Sequence in context: A355211 A211604 A032014 * A007139 A306147 A331937
KEYWORD
nonn,changed
AUTHOR
Valery A. Liskovets, Oct 10 2005
STATUS
approved

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Last modified July 24 09:23 EDT 2024. Contains 374583 sequences. (Running on oeis4.)