%I #7 Jun 14 2021 03:12:14
%S 1,0,2,1,6,6,28,53,229,712,3336,15099,82419,477584,3086563,21566457,
%T 164113460,1350167015,12007072739,115165535180
%N Number of unlabeled 2-connected simple bipartite graphs with no cycles of length 4.
%C Also: Number of unlabeled 2-connected simple bipartite graphs with girth at least 6.
%e For n=8 the a(8)=2 solutions are an 8-cycle and a theta graph consisting of two vertices joined by three paths of length 3.
%K nonn,hard,more
%O 6,3
%A _Brendan McKay_, Jun 14 2021