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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 (list; graph; refs; listen; history; text; internal format)
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.

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

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Last modified October 22 14:44 EDT 2019. Contains 328318 sequences. (Running on oeis4.)