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 A297385 #20 Feb 16 2025 08:33:52 %S A297385 2,40,8616,15639936,242230440480,32098460087825856, %T A297385 36433115190009846104160 %N A297385 Number of Eulerian cycles in the n X n torus grid graph. %C A297385 a(3) is also the number of Eulerian cycles in the 3 X 3 rook graph. %C A297385 a(4) is also the number of Eulerian cycles in the 4-hypercube (tesseract) graph Q_4. %H A297385 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/EulerianCycle.html">Eulerian Cycle</a> %H A297385 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TorusGridGraph.html">Torus Grid Graph</a> %Y A297385 Main diagonal of A298117. %Y A297385 Cf. A054759, A212803. %K A297385 nonn,more %O A297385 1,1 %A A297385 _Eric W. Weisstein_, Dec 29 2017 %E A297385 a(4)-a(7) from _Andrew Howroyd_, Jan 12 2018 %E A297385 a(1)-a(2) from _Andrew Howroyd_, Jan 12 2018