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 A287023 #12 Feb 16 2025 08:33:46 %S A287023 0,1,2,5,13,43,186,1187,13006,270900,11286208 %N A287023 Number of simple disconnected weakly perfect graphs on n vertices. %C A287023 First differs from A287008 (number of simple disconnected graphs with equal chromatic and fractional chromatic number) at a(8). %H A287023 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DisconnectedGraph.html">Disconnected Graph</a> %H A287023 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/WeaklyPerfectGraph.html">Weakly Perfect Graph</a> %F A287023 a(n) = A198634(n) - A287009(n). %Y A287023 Cf. A198634 (number of not necessarily connected simple weakly perfect graphs). %Y A287023 Cf. A287009 (number of not connected simple weakly perfect graphs). %Y A287023 Cf. A287008 (number of simple disconnected graphs with equal chromatic and fractional chromatic number). %K A287023 nonn,more %O A287023 1,3 %A A287023 _Eric W. Weisstein_, May 18 2017 %E A287023 a(11) from formula by _Falk Hüffner_, Aug 13 2017