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Number of prime graphs on n vertices. (G is prime iff G has no module. Modules are also called homogeneous sets.)
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%I #12 Sep 03 2021 02:01:10

%S 0,0,0,1,4,26,260,4670,145870,8110356,804203096

%N Number of prime graphs on n vertices. (G is prime iff G has no module. Modules are also called homogeneous sets.)

%C A set of vertices S is called a module if every vertex outside S either sees all vertices in S or none of them. S must be > 1 and < size of the graph.

%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 The smallest prime graph and only one on 4 vertices is the 4-path. The 4 graphs on 5 vertices are: P5, C5, House and Bull.

%K more,nonn

%O 1,5

%A _Jim Nastos_, Jan 15 2003

%E a(10) and a(11) added using tinygraph by _Falk Hüffner_, Jan 15 2016