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 A380805 #38 Feb 25 2025 05:13:37 %S A380805 1,0,0,1,1,1,2,2,3,4,7,10,18,27,49,81,147,256,476,858,1612,2991,5676, %T A380805 10729,20575,39423,76232,147602,287518,561195,1100190,2161552,4261059, %U A380805 8418035,16675006,33098322,65844566,131233923,262066375,524224509,1050414569 %N A380805 Number of unlabeled simple connected graphs with n nodes of degree at most 3 and each node a member of exactly one cycle. %C A380805 All such graphs are cactus graphs (with bridges allowed). %H A380805 Andrew Howroyd, <a href="/A380805/b380805.txt">Table of n, a(n) for n = 0..1000</a> %H A380805 Wikipedia, <a href="https://en.wikipedia.org/wiki/Cactus_graph">Cactus graph</a>. %H A380805 <a href="/index/Ca#cacti">Index entries for sequences related to cacti</a>. %o A380805 (PARI) Vec(G(40)) \\ G() defined in A380633. - _Andrew Howroyd_, Feb 24 2025 %Y A380805 Row sums of A380633. %Y A380805 Cf. A000083, A001349, A317722, A380632 (nodes of any degree). %K A380805 nonn %O A380805 0,7 %A A380805 _Gordon Hamilton_, Feb 23 2025 %E A380805 a(13) onwards from _Andrew Howroyd_, Feb 24 2025