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 A218463 #19 Feb 16 2025 08:33:18 %S A218463 1,5,95,10297,11546911 %N A218463 Number of simple connected perfect matching graphs on 2n nodes. %C A218463 Perfect matchings exist only for graphs with an even number of nodes. %H A218463 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ConnectedGraph.html">Connected Graph</a> %H A218463 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PerfectMatching.html">Perfect Matching</a> %F A218463 a(n) = A218462(n) - A287652(n). - _Eric W. Weisstein_, May 29 2017 %F A218463 Inverse Euler transform of A218462. - _Andrew Howroyd_, Nov 03 2017 %Y A218463 Cf. A218462 (not-necessarily-connected simple perfect matching graphs). %Y A218463 Cf. A287652 (disconnected simple perfect matching graphs). %K A218463 nonn,more %O A218463 1,2 %A A218463 _Eric W. Weisstein_, Mar 26 2013