A240973 The number of switching equivalent classes of cube root edge weighted graphs.

2, 4, 14, 120, 3222, 271287, 64154817, 41653775052, 74220906305025, 364602274426789164

Offset

3,1

Comments

a(n) is also the number of cube root two-graphs, up to isomorphism.

Links

Table of n, a(n) for n=3..12.

Y. Cheng and A. L. Wells,  Switching classes of directed graphs, Journal of Combinatorial Theory, Series B, Vol. 40-2 (1986), p. 169-186.

T. R. Hoffman and J. P. Solazzo, Complex two-graphs via equiangular tight frames, arXiv preprint, arXiv:1408.0334 [math.CO], 2014.

Crossrefs

Sequence in context: A167008 A329234 A238638 * A102449 A193520 A102897

Adjacent sequences: A240970 A240971 A240972 * A240974 A240975 A240976

Keyword

nonn,more

Author

Thomas R. Hoffman, Aug 05 2014

Extensions

a(8)-a(12) added by Andrew Howroyd, Aug 31 2018

Status

approved