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A153846 Number of non-isomorphic I-graphs I(n,j,k) on 2n vertices (1<=j,k<=Floor[(n-1)/2]). 1
1, 1, 2, 3, 2, 4, 4, 6, 3, 11, 4, 7, 10, 10, 5, 14, 5, 17, 12, 11, 6, 28, 10, 14, 13, 21, 8, 35, 8, 22, 17, 18, 17, 41, 10, 19, 20, 40, 11, 44, 11, 31, 32, 23, 12, 60, 16, 36, 25, 37, 14, 49, 24, 50, 27, 30, 15, 93, 16, 31, 40, 46, 29, 64, 17, 47, 32, 63, 18, 96, 19, 38, 49, 51, 30 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,3

COMMENTS

The I-graph I(n,j,k) is a graph with vertex set V(I(n,j,k)) = {u_0,u_1,...,u_{n-1},v_0,v_1,...,v_{n-1}} and edge set E(I(n,j,k)) = {u_i u_{i+j}, u_i v_i, v_i v_{i+k} : i=0,...,n-1}, where the subscripts are to be read modulo n. The I-graphs 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 0-919611-19-2.

LINKS

Table of n, a(n) for n=3..77.

Marko Boben, Tomaz Pisanski, Arjana Zitnik, I-graphs and the corresponding configurations J. Combin. Des. 13 (2005), no. 6, 406--424.

B. Horvat, T. Pisanski; A. Zitnik.  Isomorphism checking of I-graphs, Graphs Comb. 28, No. 6, 823-830 (2012).

M. Watkins, A theorem on Tait colorings with an application to the generalized Petersen graphs, J. Combin. Theory 6 (1969), 152-164.

Eric Weisstein's World of Mathematics, Graph Expansion

CROSSREFS

Cf. A077105, A153847.

Sequence in context: A182762 A173997 A029143 * A284383 A072406 A297117

Adjacent sequences:  A153843 A153844 A153845 * A153847 A153848 A153849

KEYWORD

nonn

AUTHOR

Tomaz Pisanski, Jan 08 2009

STATUS

approved

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Last modified January 25 16:42 EST 2020. Contains 331245 sequences. (Running on oeis4.)