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 A187237 #15 Feb 16 2025 08:33:14 %S A187237 0,0,0,0,1,7,129,3312,134303,8594350,894307856,158323596832 %N A187237 Number of simple connected imperfect graphs on n vertices. %H A187237 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ImperfectGraph.html">Imperfect Graph.</a> %F A187237 a(n) = A001349(n) - A052433(n). %Y A187237 Cf. A001349, A052433, A187236. %K A187237 nonn,more,hard %O A187237 1,6 %A A187237 _Eric W. Weisstein_, Mar 07 2011 %E A187237 a(12) using formula by _Falk Hüffner_, Jan 15 2016