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.
%I A084280 #17 Feb 16 2025 08:32:49 %S A084280 1,2,8,64,1023,32596,2062592,257798069,63135260853,29939766625614, %T A084280 27055039857514327 %N A084280 Number of labeled 4-colorable (i.e., chromatic number <= 4) graphs on n nodes. %H A084280 S. R. Finch, <a href="http://www.people.fas.harvard.edu/~sfinch/">Bipartite, k-colorable and k-colored graphs</a> %H A084280 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 A084280 F. Hüffner, <a href="https://github.com/falk-hueffner/tinygraph">tinygraph</a>, software for generating integer sequences based on graph properties, version 8c665c7 %H A084280 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/n-ColorableGraph.html">n-Colorable Graph</a> %Y A084280 Cf. A047864, A084279, A084281, A084282. %K A084280 nonn,more %O A084280 1,2 %A A084280 _Eric W. Weisstein_, May 25 2003 %E A084280 a(7)-a(11) added using tinygraph by _Falk Hüffner_, Jun 20 2018