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 A249905 #16 Aug 13 2020 14:02:28 %S A249905 2,1,5,4,5,6,5,6,6,7,6,7,5,8,6,7,6,7,6,7,7,8,7,7,6,8,7,7,7,8,7,8,7,7, %T A249905 7,8,6,8,7,8,7,8,8,8,8,7,8,8,7,8,8,8,7,8,8,8,8,8,8,8,6,8,7,8,8,8,8,8, %U A249905 8,8,7,8,7,8,8,8,7,8,8,8,7,8,8,8,8,8,8,8,8,9 %N A249905 Smallest number of vertices supporting a graph with exactly n Hamiltonian cycles up to direction. %C A249905 "Up to direction" means that cycles differing only in starting vertex or direction of traversal are treated as one cycle. a(n) always exists since the wheel graph on n spokes has n cycles. %H A249905 Jeremy Tan, <a href="/A249905/b249905.txt">Table of n, a(n) for n = 0..4890</a> %H A249905 Andreas Björklund, <a href="http://arxiv.org/abs/1008.0541">Determinant Sums for Undirected Hamiltonicity</a>, arXiv preprint arXiv:1008.0541 [cs.DS], 2010. %H A249905 Erich Friedman, <a href="https://erich-friedman.github.io/mathmagic/0912.html">Math Magic</a> (September 2012) %e A249905 a(3) = 4 since K_4 has 3 Hamiltonian cycles up to direction. %Y A249905 Cf. A244511 (a(n) <= 7), A249906 (records), A305190. %K A249905 nonn,hard %O A249905 0,1 %A A249905 _Jeremy Tan_, Nov 08 2014