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 A243272 #17 Feb 18 2025 15:35:21 %S A243272 1,0,1,1,2,5,21,120,1312,26525,1073690,84471633 %N A243272 Number of unlabeled simple graphs with n nodes that are Hamiltonian and Eulerian. %H A243272 Travis Hoppe and Anna Petrone, <a href="https://github.com/thoppe/Encyclopedia-of-Finite-Graphs">Encyclopedia of Finite Graphs</a>. %H A243272 Travis Hoppe and Anna Petrone, <a href="http://arxiv.org/abs/1408.3644">Integer sequence discovery from small graphs</a>, arXiv preprint arXiv:1408.3644 [math.CO], 2014. %H A243272 Falk Hüffner, <a href="https://github.com/falk-hueffner/tinygraph">tinygraph</a>, software for generating integer sequences based on graph properties, version a1db88e. %H A243272 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/EulerianGraph.html">Eulerian Graph</a>. %H A243272 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HamiltonianGraph.html">Hamiltonian Graph</a>. %Y A243272 Cf. A003216 (Hamiltonian graphs), A003049 (Eulerian graphs). %K A243272 nonn,more %O A243272 1,5 %A A243272 _Travis Hoppe_ and _Anna Petrone_, Jun 02 2014 %E A243272 a(10)-a(11) added using tinygraph by _Falk Hüffner_, Aug 15 2017