%I #20 Feb 07 2024 23:27:30

%S 1,0,0,1,1,2,5,9,22,60,164,494,1624,5602,20600,79813,323806,1371025,

%T 6034105,27513424,129641411,629862824,3149541908,16183100922,

%U 85328280263,461123500894,2551342936264,14438734591483,83506198920054,493163726073210,2971858162771887

%N a(n) is the number of unlabeled connected graphs without endpoints with n edges.

%H Andrew Howroyd, <a href="/A342556/b342556.txt">Table of n, a(n) for n = 0..50</a>

%H 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 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 Inverse Euler transform of A369290.

%Y Row sums of A342557.

%Y Cf. A004108 (n vertices), A307317 (multigraph), A369290 (not necessarily connected).

%K nonn

%O 0,6

%A _Hugo Pfoertner_, May 21 2021

%E a(0)=1 prepended and a(25) onwards from _Andrew Howroyd_, Feb 01 2024