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 A307930 #9 Feb 16 2025 08:33:55 %S A307930 0,0,1,16,3216,9748992,554701578240,690468767270830080 %N A307930 Number of (undirected) Hamiltonian circuits in the n-triangular graph. %H A307930 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HamiltonianCycle.html">Hamiltonian Cycle</a> %H A307930 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TriangularGraph.html">Triangular Graph</a> %F A307930 a(n) = A129349(n)/2. %Y A307930 Cf. A129349. %K A307930 nonn,more,hard %O A307930 2,4 %A A307930 _Eric W. Weisstein_, May 06 2019