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

1,6

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.

Links

Table of n, a(n) for n=1..19.

Brendan McKay, nauty software that can generate these graphs.

Wikipedia, Chordal bipartite graph.

Example

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

Crossrefs

Cf. A371867, A371868.

Sequence in context: A075277 A370061 A192874 * A159557 A176756 A054094

Adjacent sequences: A371866 A371867 A371868 * A371870 A371871 A371872

Keyword

nonn,hard,more

Author

Brendan McKay, Apr 09 2024

Status

approved