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 A342556 #20 Feb 07 2024 23:27:30 %S A342556 1,0,0,1,1,2,5,9,22,60,164,494,1624,5602,20600,79813,323806,1371025, %T A342556 6034105,27513424,129641411,629862824,3149541908,16183100922, %U A342556 85328280263,461123500894,2551342936264,14438734591483,83506198920054,493163726073210,2971858162771887 %N A342556 a(n) is the number of unlabeled connected graphs without endpoints with n edges. %H A342556 Andrew Howroyd, <a href="/A342556/b342556.txt">Table of n, a(n) for n = 0..50</a> %H A342556 Brendan McKay and Adolfo Piperno, <a href="https://doi.org/10.1016/j.jsc.2013.09.003">Practical Graph Isomorphism, II</a>, Journal of Symbolic Computation, 60 (2014), pp. 94-112. %H A342556 Brendan McKay and Adolfo Piperno, <a href="http://pallini.di.uniroma1.it/">nauty and Traces</a>, programs for computing automorphism groups of graphs and digraphs. %F A342556 Inverse Euler transform of A369290. %Y A342556 Row sums of A342557. %Y A342556 Cf. A004108 (n vertices), A307317 (multigraph), A369290 (not necessarily connected). %K A342556 nonn %O A342556 0,6 %A A342556 _Hugo Pfoertner_, May 21 2021 %E A342556 a(0)=1 prepended and a(25) onwards from _Andrew Howroyd_, Feb 01 2024