A130315 Number of nontrivial (girth >=5) snarks on 2n nodes.

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

Offset

1,9

Comments

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

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 [math.CO], 2012-2013.

G. Brinkmann, J. Goedgebeur, J. Hagglund, and K. Markstrom, Generation and properties of Snarks, J. Comb. Theory, Series B, 103 (4) (2013), 468-488.

J. Hagglund and K. Markstrom, On stable cycles and cycle double covers of graphs with large circumference, Discrete Math., 312 (2012), 2540-2544.

House of Graphs, Snarks

Eric Weisstein's World of Mathematics, Snark

Crossrefs

Sequence in context: A218883 A353699 A202963 * A087150 A323724 A214307

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 Hagglund-Markstrom by N. J. A. Sloane, Jul 26 2012

a(17), a(18) added by Jan Goedgebeur, Jul 31 2012

Status

approved