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 A371867 #7 Apr 10 2024 09:34:11 %S A371867 1,2,3,7,13,34,84,270,912,3755,17169,90953,538858,3586559,26459702, %T A371867 215517278,1925402918,18785105127,199301164172 %N A371867 Number of chordal bipartite graphs on n unlabeled vertices. %C A371867 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 A371867 Brendan McKay, <a href="https://users.cecs.anu.edu.au/~bdm/nauty/">nauty software </a> that can generate these graphs. %H A371867 Wikipedia, <a href="https://en.wikipedia.org/wiki/Chordal_bipartite_graph">Chordal bipartite graph</a>. %e A371867 For n=3, the three examples are the two disconnected graphs and the path. %Y A371867 Cf. A371868, A371869. %K A371867 nonn,hard,more %O A371867 1,2 %A A371867 _Brendan McKay_, Apr 09 2024