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 A301648 #10 Feb 16 2025 08:33:53 %S A301648 0,1,5,6,226,1072,255088,4638576,6663430912,467260456608, %T A301648 3916162476483538,1076226888605605706,51249820944023435573470, %U A301648 56126499620491437281263608,14870957102232406137455708164254,65882516522625836326159786165530572,95494789899510664733921727510895952184006 %N A301648 Number of longest cycles in the n X n grid graph. %C A301648 a(10) = 467260456608. %H A301648 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GraphCycle.html">Graph Cycle</a> %H A301648 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GridGraph.html">Grid Graph</a> %F A301648 a(2n) = A003763(n). %F A301648 a(2n+1) = A181584(n). - _Andrew Howroyd_, Mar 01 2020 %Y A301648 Cf. A137932 (circumference of the (n-1) X (n-1) grid graph). %Y A301648 Cf. A003763 (number of Hamiltonian cycles in the 2n X 2n grid graph). %Y A301648 Cf. A181584 (number of longest cycles in the (2n+1) X (2n+1) grid graph). %K A301648 nonn %O A301648 1,3 %A A301648 _Eric W. Weisstein_, Mar 25 2018 %E A301648 Terms a(9) and beyond from _Andrew Howroyd_, Mar 01 2020