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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,9

COMMENTS

Snarks are cyclically 4-edge 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), 2540-2544.

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

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

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

STATUS

approved

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Last modified December 5 07:11 EST 2016. Contains 278761 sequences.