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 A326208 #9 Jun 21 2019 07:57:40
%S A326208 0,1,0,1,10,218,10078,896756,151676112,47754337568,28229412456056,
%T A326208 31665593711174080
%N A326208 Number of Hamiltonian labeled simple graphs with n vertices.
%C A326208 A graph is Hamiltonian if it contains a cycle passing through every vertex exactly once.
%H A326208 F. Hüffner, <a href="https://github.com/falk-hueffner/tinygraph">tinygraph</a>, software for generating integer sequences based on graph properties, version 9766535.
%H A326208 Wikipedia, <a href="https://en.wikipedia.org/wiki/Hamiltonian_path">Hamiltonian path</a>
%H A326208 Gus Wiseman, <a href="/A326208/a326208.png">The a(5) = 218 simple graphs containing a Hamiltonian cycle.</a>
%F A326208 A006125(n) = a(n) + A326207(n).
%t A326208 Table[Length[Select[Subsets[Subsets[Range[n],{2}]],FindHamiltonianCycle[Graph[Range[n],#]]!={}&]],{n,0,4}] (* Mathematica 8.0+ *)
%Y A326208 The unlabeled version is A003216.
%Y A326208 The directed version is A326204 (with loops) or A326219 (without loops).
%Y A326208 Simple graphs not containing a Hamiltonian cycle are A326207.
%Y A326208 Simple graphs containing a Hamiltonian path are A326206.
%Y A326208 Cf. A003216, A006125, A057864, A283420.
%K A326208 nonn,more
%O A326208 0,5
%A A326208 _Gus Wiseman_, Jun 15 2019
%E A326208 a(7)-a(11) added using tinygraph by _Falk Hüffner_, Jun 21 2019