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 A283420 #23 Feb 16 2025 08:33:42 %S A283420 0,1,2,6,16,65,310,2316,26241,522596,18766354 %N A283420 Number of simple (not necessarily connected) untraceable graphs on n nodes. %H A283420 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/UntraceableGraph.html">Untraceable Graph</a> %H A283420 Wikipedia, <a href="https://en.wikipedia.org/wiki/Hamiltonian_path">Hamiltonian path</a> %H A283420 Gus Wiseman, <a href="http://arxiv.org/abs/0709.0430">Enumeration of paths and cycles and e-coefficients of incomparability graphs</a>, arXiv:0709.0430 [math.CO], 2007. %H A283420 Gus Wiseman, <a href="/A283420/a283420_1.png">The a(5) = 16 unlabeled simple graphs not containing a Hamiltonian path</a>. %F A283420 a(n) = A000088(n) - A057864(n). %Y A283420 Cf. A000088 (number of simple graphs on n vertices). %Y A283420 Cf. A057864 (number of simple traceable graphs on n vertices). %Y A283420 Cf. A283421 (number of simple connected untraceable graphs on n vertices). %Y A283420 The labeled case is A326205. %Y A283420 The directed case is A326224 (with loops). %Y A283420 Unlabeled simple graphs not containing a Hamiltonian cycle are A246446. %Y A283420 Cf. A003216, A326206, A326217, A326221. %K A283420 nonn,more %O A283420 1,3 %A A283420 _Eric W. Weisstein_, May 14 2017