

A153847


Number of nonisomorphic connected Igraphs I(n,j,k) on 2n vertices (1<=j,k<=Floor[(n1)/2]).


1



1, 1, 2, 2, 2, 3, 3, 4, 3, 7, 4, 5, 7, 6, 5, 8, 5, 10, 9, 8, 6, 14, 8, 10, 9, 13, 8, 19, 8, 12, 13, 13, 13, 19, 10, 14, 15, 20, 11, 25, 11, 19, 19, 17, 12, 26, 14, 22, 19, 22, 14, 26, 19, 26, 21, 22, 15, 40, 16, 23, 25, 24, 23, 37, 17, 28, 25, 37, 18, 38, 19, 28, 31, 31, 25, 43, 20
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OFFSET

3,3


COMMENTS

The Igraph I(n,j,k) is a graph with vertex set V(I(n,j,k)) = {u_0,u_1,...,u_{n1},v_0,v_1,...,v_{n1}} and edge set E(I(n,j,k)) = {u_i u_{i+j}, u_i v_i, v_i v_{i+k} : i=0,...,n1}, where the subscripts are to be read modulo n. The Igraphs generalize the family of generalized Petersen graphs.


REFERENCES

I. Z. Bouwer, W. W. Chernoff, B. Monson and Z. Star, The Foster Census (Charles Babbage Research Centre, 1988), ISBN 0919611192.


LINKS

Table of n, a(n) for n=3..79.
Marko Boben, Tomaz Pisanski, Arjana Zitnik, Igraphs and the corresponding configurations J. Combin. Des. 13 (2005), no. 6, 406424.
M. Watkins, A theorem on Tait colorings with an application to the generalized Petersen graphs, J. Combin. Theory 6 (1969), 152164.
Eric Weisstein's World of Mathematics, Graph Expansion


CROSSREFS

Cf. A077105, A153846.
Sequence in context: A271519 A077105 A173752 * A332246 A096036 A108504
Adjacent sequences: A153844 A153845 A153846 * A153848 A153849 A153850


KEYWORD

nonn


AUTHOR

Tomaz Pisanski, Jan 08 2009


STATUS

approved



