

A084565


Number of connected switching classes of signed graphs with n nodes.


1



1, 1, 3, 12, 79, 1123, 42065, 4880753, 1674021742, 1612191702946, 4291399235883144, 31570649902282023158, 644451747846907273827686, 36675914469877423648734408329, 5846124500387959287169919356171145
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OFFSET

1,3


COMMENTS

Also, number of unlabeled connected strength 2 Eulerian graphs with n nodes.  Vladeta Jovovic, Mar 14 2009


REFERENCES

Bussemaker, F. C.; Cameron, P. J.; Seidel, J. J.; and Tsaranov, S. V., Tables of signed graphs, ReportWSK 9101, Eindhoven University of Technology, Department of Mathematics and Computing Science, Eindhoven, 1991, 105 pp. MR: 92g:05001.


LINKS

Table of n, a(n) for n=1..15.
F. C. Bussemaker, P. J. Cameron, J. J. Seidel, and S. V. Tsaranov, Tables of signed graphs, ReportWSK 9101, Eindhoven University of Technology, Department of Mathematics and Computing Science, Eindhoven, 1991, 105 pp. (MR: 92g:05001).


CROSSREFS

Cf. A007127, A053465.
Sequence in context: A058107 A213139 A023879 * A323634 A275488 A304561
Adjacent sequences: A084562 A084563 A084564 * A084566 A084567 A084568


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Jul 16 2003


EXTENSIONS

Edited by N. J. A. Sloane Apr 05 2009 at the suggestion of Vladeta Jovovic


STATUS

approved



