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 A308144 #10 Feb 16 2025 08:33:55 %S A308144 1,3,12,114,1968,66312,4381020,578266212,153350225268,82409298702462, %T A308144 90180040305841212,201800030110625440248,926548406689594565864346, %U A308144 8752381854153235620928637604 %N A308144 Number of (undirected) Hamiltonian paths on the triangular grid with n vertices on each side. %H A308144 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HamiltonianPath.html">Hamiltonian Path</a> %H A308144 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TriangularGridGraph.html">Triangular Grid Graph</a> %F A308144 a(n) = A112675(n)/2 for n > 1. %Y A308144 Cf. A112675, A112676, A266513, A288148. %K A308144 nonn %O A308144 1,2 %A A308144 _Eric W. Weisstein_, May 14 2019 %E A308144 a(1) corrected by _Andrew Howroyd_, Jan 19 2022