A371868 -id:A371868 - cp's OEIS frontend

A371867 Number of chordal bipartite graphs on n unlabeled vertices.

1, 2, 3, 7, 13, 34, 84, 270, 912, 3755, 17169, 90953, 538858, 3586559, 26459702, 215517278, 1925402918, 18785105127, 199301164172

Offset: 1

Brendan McKay, Apr 09 2024

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.

			For n=3, the three examples are the two disconnected graphs and the path.

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

Cf. A371868, A371869.

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

Original entry on oeis.org

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

Offset: 1

Brendan McKay, Apr 09 2024

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.

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

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

Cf. A371867, A371868.

cp's OEIS Frontend

A371867 Number of chordal bipartite graphs on n unlabeled vertices.

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