login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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.

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 28 17:22 EST 2022. Contains 358421 sequences. (Running on oeis4.)