login
A098634
Consider the family of multigraphs enriched by the species of even sets. Sequence gives number of those multigraphs with 2n loops and arcs.
0
1, 2, 41, 2627, 357716, 86570987, 33355085381, 19002804068432, 15177169622020811, 16322141415741150887, 22901431199026692596006, 40870032497467496395428677, 90848469347406506760349066541, 247166310906569012786184536033402, 810867121877912775078998948740650941
OFFSET
0,2
REFERENCES
G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.
LINKS
G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004. [Cached copy, with permission]
FORMULA
E.g.f.: exp(-1)*Sum_{n>=0}cosh(x)^(n^2)/n!. - Vladeta Jovovic, Mar 04 2008
CROSSREFS
Sequence in context: A133298 A054742 A113634 * A278847 A297007 A193270
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Oct 26 2004
EXTENSIONS
More terms from Vladeta Jovovic, Mar 04 2008
STATUS
approved