A371868 - OEIS

A371868

Number of connected chordal bipartite graphs on n unlabeled vertices.

1, 1, 1, 3, 5, 16, 41, 154, 560, 2550, 12404, 69536, 428698, 2947229, 22288540, 185226859, 1682006569, 16635022967, 178525323313

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,4

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

The 3 examples for n=4 are the 4-cycle, the star, and the path.

CROSSREFS

Cf. A371867, A371869.

Sequence in context: A300533 A221783 A368409 * A243321 A099101 A208819

Adjacent sequences: A371865 A371866 A371867 * A371869 A371870 A371871

KEYWORD

nonn,hard,more

AUTHOR

Brendan McKay, Apr 09 2024

STATUS

approved