A079577 Number of unlabeled, connected graphs on n vertices that have no induced subgraph isomorphic to a bull, a P5 or a P5-bar.

1, 1, 2, 6, 18, 67, 248, 1005, 4068, 16955, 71090, 302194, 1294752, 5598368, 24382450

Offset

1,3

Comments

Bull = 4-path with a 5th vertex adjacent to the two middle vertices of the path P5 = path on 5 vertices P5-bar = complement of a P5

Links

Table of n, a(n) for n=1..15.

J. L. Fouquet, A Decomposition for a class of (P5,P5-bar)-free graphs, Discrete Math. 121 (1993) 75-83.

F. Hüffner, tinygraph, software for generating integer sequences based on graph properties, version 6e0a59d.

Example

O.........O
|.........|
.\......./
..O-----O bull
...\.../
....\./
.....O

Crossrefs

Cf. A267602 (with additional "prime" requirement)

Sequence in context: A173385 A057693 A053496 * A150078 A150079 A150080

Adjacent sequences: A079574 A079575 A079576 * A079578 A079579 A079580

Keyword

more,nonn

Author

Jim Nastos, Jan 24 2003

Extensions

a(10)-a(15) added using tinygraph by Falk Hüffner, Jan 15 2016

Definition corrected ("are prime" omitted) by Falk Hüffner, Jan 18 2016

Status

approved