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A079473 Number of prime graphs on n vertices (G is prime iff G has no module. Module are also called homogeneous sets). 0
0, 0, 0, 1, 4, 26, 260, 4670, 145870, 8110356, 804203096 (list; graph; refs; listen; history; text; internal format)
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

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Last modified February 23 15:24 EST 2020. Contains 332167 sequences. (Running on oeis4.)