A267653 Number of unlabeled, connected graphs on n vertices which have no induced subgraph isomorphic to an R-graph.

1, 1, 2, 6, 21, 111, 818, 9825, 195759, 6622127, 368949015

Offset

1,3

Comments

The R-graph has 6 vertices. 4 vertices form a cycle and both the other two vertices are adjacent to a single one of those 4.

Links

Table of n, a(n) for n=1..11.

F. Hüffner, tinygraph, software for generating integer sequences based on graph properties, version e8699da.

Crossrefs

Cf. A079570, the same for the cricket graph (like an R-graph, but with a triangle instead of a 4-cycle).

Sequence in context: A156808 A245882 A374617 * A245880 A076324 A303032

Adjacent sequences: A267650 A267651 A267652 * A267654 A267655 A267656

Keyword

nonn,more

Author

Falk Hüffner, Jan 19 2016

Status

approved