

A130315


Number of nontrivial (girth >=5) snarks on 2n nodes.


2



0, 0, 0, 0, 1, 0, 0, 0, 2, 6, 20, 38, 280, 2900, 28399, 293059, 3833587, 60167732
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OFFSET

1,9


COMMENTS

Snarks are cyclically 4edge connected cubic graphs with chromatic index 4 and girth >= 5.


REFERENCES

J. Hagglund and K. Markstrom, On stable cycles and cycle double covers of graphs with large circumference, Discrete Math., 312 (2012), 25402544.
G. Brinkmann, J. Goedgebeur, J. Hagglund, and K. Markstrom, Generation and properties of Snarks, J. Comb. Theory, Series B, 103 (4) (2013), 468488.


LINKS

Table of n, a(n) for n=1..18.
G. Brinkmann, J. Goedgebeur, J. Hagglund, and K. Markstrom, Generation and properties of Snarks, arxiv 1206.6690 (2012)
House of Graphs, Snarks
Eric Weisstein's World of Mathematics, Snark


CROSSREFS

Sequence in context: A181558 A218883 A202963 * A087150 A214307 A087134
Adjacent sequences: A130312 A130313 A130314 * A130316 A130317 A130318


KEYWORD

nonn,hard,more


AUTHOR

Eric W. Weisstein, May 22, 2007


EXTENSIONS

a(15), a(16) added from HagglundMarkstrom.  N. J. A. Sloane, Jul 26 2012
a(17), a(18) added by Jan Goedgebeur, Jul 31 2012


STATUS

approved



