A079577 - OEIS

%I #19 Jan 20 2016 04:19:11

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

%T 24382450

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

%C 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

%H J. L. Fouquet, <a href="http://dx.doi.org/10.1016/0012-365X(93)90539-6">A Decomposition for a class of (P5,P5-bar)-free graphs</a>, Discrete Math. 121 (1993) 75-83.

%H F. Hüffner, <a href="https://github.com/falk-hueffner/tinygraph">tinygraph</a>, software for generating integer sequences based on graph properties, version 6e0a59d.

%e O.........O

%e |.........|

%e .\......./

%e ..O-----O bull

%e ...\.../

%e ....\./

%e .....O

%Y Cf. A267602 (with additional "prime" requirement)

%K more,nonn

%O 1,3

%A _Jim Nastos_, Jan 24 2003

%E a(10)-a(15) added using tinygraph by _Falk Hüffner_, Jan 15 2016

%E Definition corrected ("are prime" omitted) by _Falk Hüffner_, Jan 18 2016