A084565 Number of connected switching classes of signed graphs with n nodes.

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

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, Report-WSK 91-01, 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, Report-WSK 91-01, Eindhoven University of Technology, Department of Mathematics and Computing Science, Eindhoven, 1991, 105 pp. (MR: 92g:05001).

Crossrefs

Cf. A007127, A053465.

Sequence in context: A213139 A023879 A380028 * A323634 A373395 A275488

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