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 A380632 #8 Feb 24 2025 16:32:30 %S A380632 1,0,0,1,1,1,2,2,3,5,9,14,28,49,95,182,369,733,1509,3103,6504,13627, %T A380632 28949,61701,132457,285454,618863,1346022,2940287,6444364,14172744, %U A380632 31257883,69142445,153333476,340880766,759549740,1696122213,3795178540,8508326129,19109193805,42991993545,96881110654 %N A380632 Number of simple connected graphs on n unlabeled nodes with each node a member of exactly one cycle. %C A380632 All such graphs are cactus graphs (with bridges allowed). %H A380632 Andrew Howroyd, <a href="/A380632/b380632.txt">Table of n, a(n) for n = 0..1000</a> %H A380632 Wikipedia, <a href="https://en.wikipedia.org/wiki/Cactus_graph">Cactus graph</a>. %H A380632 <a href="/index/Ca#cacti">Index entries for sequences related to cacti</a>. %o A380632 (PARI) Vec(G(40)) \\ G() defined in A380631. %Y A380632 Row sums of A380631. %Y A380632 Cf. A000083, A380805. %K A380632 nonn %O A380632 0,7 %A A380632 _Andrew Howroyd_, Feb 24 2025