A079473 Number of prime graphs on n vertices. (G is prime iff G has no module. Modules are also called homogeneous sets.)

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

Offset

1,5

Comments

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.

Links

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

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

Example

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.

Crossrefs

Sequence in context: A215266 A002465 A248668 * A145164 A113078 A177451

Adjacent sequences: A079470 A079471 A079472 * A079474 A079475 A079476

Keyword

more,nonn

Author

Jim Nastos, Jan 15 2003

Extensions

a(10) and a(11) added using tinygraph by Falk Hüffner, Jan 15 2016

Status

approved