A362908 Number of graphs on n unlabeled nodes with treewidth 2.

0, 0, 0, 1, 4, 17, 72, 323, 1639, 9203

Offset

0,5

Links

Table of n, a(n) for n=0..9.

Wikipedia, Treewidth.

Example

There is a single graph of treewidth 2 on 3 vertices, which is the complete graph.

Prog

(SageMath) [sum(1 for g in graphs(n) if g.treewidth() == 2) for n in range(9)]

Crossrefs

Column 2 of A263294.

Sequence in context: A122451 A257388 A113442 * A085732 A289159 A083330

Adjacent sequences: A362905 A362906 A362907 * A362909 A362910 A362911

Keyword

nonn,more

Author

Martin Rubey, May 09 2023

Status

approved