%I #7 Apr 10 2024 09:34:11
%S 1,2,3,7,13,34,84,270,912,3755,17169,90953,538858,3586559,26459702,
%T 215517278,1925402918,18785105127,199301164172
%N Number of chordal bipartite graphs on n unlabeled vertices.
%C A chordal bipartite graph is a bipartite graph with no induced cycles longer than 4-cycles. Note that this is not the same as a bipartite graph which is chordal, as that would exclude all cycles. This sequence includes disconnected graphs.
%H Brendan McKay, <a href="https://users.cecs.anu.edu.au/~bdm/nauty/">nauty software </a> that can generate these graphs.
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Chordal_bipartite_graph">Chordal bipartite graph</a>.
%e For n=3, the three examples are the two disconnected graphs and the path.
%Y Cf. A371868, A371869.
%K nonn,hard,more
%O 1,2
%A _Brendan McKay_, Apr 09 2024