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Number of labeled 4-colorable (i.e., chromatic number <= 4) graphs on n nodes.
5

%I #16 Apr 14 2019 13:11:23

%S 1,2,8,64,1023,32596,2062592,257798069,63135260853,29939766625614,

%T 27055039857514327

%N Number of labeled 4-colorable (i.e., chromatic number <= 4) graphs on n nodes.

%H S. R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/">Bipartite, k-colorable and k-colored graphs</a>

%H S. R. Finch, <a href="/A191371/a191371.pdf">Bipartite, k-colorable and k-colored graphs</a>, June 5, 2003. [Cached copy, with permission of the author]

%H F. Hüffner, <a href="https://github.com/falk-hueffner/tinygraph">tinygraph</a>, software for generating integer sequences based on graph properties, version 8c665c7

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/n-ColorableGraph.html">n-Colorable Graph</a>

%Y Cf. A047864, A084279, A084281, A084282.

%K nonn,more

%O 1,2

%A _Eric W. Weisstein_, May 25 2003

%E a(7)-a(11) added using tinygraph by _Falk Hüffner_, Jun 20 2018