

A125679


Number of combinatorial 2manifolds with n vertices.


0




OFFSET

7,1


LINKS

Table of n, a(n) for n=7..12.
Basudeb Datta, Minimal Triangulations of Manifolds, 25 Jan 2007, arXiv:math/0701735


EXAMPLE

a(7) = 9 because there are exactly nine 7vertex combinatorial 2manifolds, five of which triangulate the 2sphere S^2, three of which triangulate RP^2 and one triangulates S^1 X S^1.
a(8) = 44 because there are exactly fortyfour 8vertex combinatorial 2manifolds, one of which consists of two copies of S(_4)^2, fourteen of which triangulate the 2sphere S^2, sixteen of which triangulate RP^2, seven triangulate S^1 X S^1 and six triangulate the Klein bottle.


CROSSREFS

Sequence in context: A084016 A221508 A301397 * A037207 A225488 A096688
Adjacent sequences: A125676 A125677 A125678 * A125680 A125681 A125682


KEYWORD

hard,more,nonn


AUTHOR

Jonathan Vos Post, Jan 30 2007


EXTENSIONS

Replaced arXiv URL by noncached version  R. J. Mathar, Oct 30 2009


STATUS

approved



