cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A216834 Number of weak snarks on 2n nodes.

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%I A216834 #35 Feb 16 2025 08:33:18
%S A216834 0,0,0,0,1,0,0,0,2,6,31,155,1297,12517,139854,1764950,25286953,
%T A216834 404899916
%N A216834 Number of weak snarks on 2n nodes.
%C A216834 Multiple definitions of snarks exist which vary in strength. Here snarks are cyclically 4-edge connected cubic graphs with chromatic index 4. These are sometimes called weak snarks.  Some stronger definitions require snarks to have girth >= 5 or to be cyclically 5-edge connected.
%H A216834 G. Brinkmann, J. Goedgebeur, J. Hagglund, and K. Markstrom, <a href="http://arxiv.org/abs/1206.6690">Generation and properties of Snarks</a>, arxiv 1206.6690 [math.CO], 2012-2013.
%H A216834 J. Goedgebeur, E. Máčajová and M. Škoviera, <a href="https://arxiv.org/abs/1712.07867">Smallest snarks with oddness 4 and cyclic connectivity 4 have order 44</a>, arXiv:1712.07867 [math.CO], 2017-2019.
%H A216834 House of Graphs, <a href="https://houseofgraphs.org/meta-directory/snarks">Snarks</a>
%H A216834 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/WeakSnark.html">Weak Snark</a>
%Y A216834 Cf. A130315.
%K A216834 nonn,hard,more
%O A216834 1,9
%A A216834 _Jan Goedgebeur_, Sep 19 2012
%E A216834 a(18) added by _Jan Goedgebeur_, May 31 2018