A371869 Number of 2-connected chordal bipartite graphs on n unlabeled vertices.

0, 0, 0, 1, 1, 4, 6, 26, 74, 356, 1655, 9750, 62009, 448498, 3554505, 31000909, 294772655, 3047952802, 34135465140

Offset: 1

Author

Brendan McKay, Apr 09 2024

Keywords

• nonn
• hard
• more

Comments

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.

Examples

			For n=4, the only example is the 4-cycle. For n=5, the only example is K(2,3).
		

Links

• Brendan McKay, nauty software that can generate these graphs.
• Wikipedia, Chordal bipartite graph.

Crossrefs

Cf. A371867, A371868.