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 A381326 #4 Feb 20 2025 10:11:20
%S A381326 3,744,1833840,18872165376,553245728256000,37106744352952320000,
%T A381326 4936487939183251906560000,1177983332748595472891904000000,
%U A381326 467912746454054494167896413962240000,292026962339084784352431710907924480000000,273498538086199515052362271809542396313600000000
%N A381326 Number of (undirected) Hamiltonian cycles in the complete 4-partite graph K_{n,n,n,n}.
%H A381326 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Completek-PartiteGraph.html">Complete k-Partite Graph</a>.
%H A381326 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HamiltonianCycle.html">Hamiltonian Cycle</a>.
%F A381326 a(n) = A378241(n)/2.
%t A381326 Table[(n!)^4 Expand[Hypergeometric1F1[1 - n, 2, x]^4 x^3] /. x^p_ :> p!, {n, 11}]/2
%Y A381326 Cf. A378241 (directed Hamiltonian cycles).
%K A381326 nonn
%O A381326 1,1
%A A381326 _Eric W. Weisstein_, Feb 20 2025