A362908 - OEIS

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A362908

Number of graphs on n unlabeled nodes with treewidth 2.

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

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

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