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 A084271 #12 Feb 16 2025 08:32:49 %S A084271 0,0,1,22,582,22377,1353810,134222308,22133512793,6025984082738, %T A084271 2662612877308658,1876486379430019037 %N A084271 Number of labeled 3-chromatic (i.e., chromatic number = 3) graphs on n nodes. %H A084271 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/n-ChromaticGraph.html">n-Chromatic Graph</a> %F A084271 a(n) = A084279(n) - A047864(n). - _Andrew Howroyd_, Dec 02 2018 %Y A084271 Cf. A047864, A084270, A084272, A084279. %K A084271 nonn,more %O A084271 1,4 %A A084271 _Eric W. Weisstein_, May 24 2003 %E A084271 a(7)-a(12) from _Andrew Howroyd_, Dec 02 2018