

A079577


Number of unlabeled, connected graphs on n vertices that have no induced subgraph isomorphic to a bull, a P5 or a P5bar.


1



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

1,3


COMMENTS

Bull = 4path with a 5th vertex adjacent to the two middle vertices of the path P5 = path on 5 vertices P5bar = complement of a P5


LINKS

Table of n, a(n) for n=1..15.
J. L. Fouquet, A Decomposition for a class of (P5,P5bar)free graphs, Discrete Math. 121 (1993) 7583.
F. Hüffner, tinygraph, software for generating integer sequences based on graph properties, version 6e0a59d.


EXAMPLE

O.........O
.........
.\......./
..OO 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



