A079457 - OEIS

A079457

Number of unlabeled and connected graphs which are weakly chordal. (G is weakly chordal iff there are no induced cycles of size 5 or more in G nor in its complement.)

1, 1, 2, 6, 20, 103, 706, 7423, 116476, 2730992, 92711668, 4435835227

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

COMMENTS

Also known as the "weakly triangulated" graphs. Contains the chordal and cochordal graphs and is contained in the class of Perfect graphs.

LINKS

Table of n, a(n) for n=1..12.

R. Hayward, Weakly triangulated graphs, Journal Comb. Theory (Series B) 39 (1985) 200-208.

R. Hayward, Generating Weakly Triangulated Graphs, Journal of Graph Theory 21 (1996) 67-69.

R. Hayward, J. Spinrad, R. Sritharan, Weakly Chordal Graph Algorithms via Handles, Proc. 11th SODA (2000) 42-49.

F. Hüffner, tinygraph, software for generating integer sequences based on graph properties, version 26b03c7

FORMULA

Inverse Euler transform of A123472.

CROSSREFS

Sequence in context: A049379 A003094 A073964 * A321911 A079455 A052433

Adjacent sequences: A079454 A079455 A079456 * A079458 A079459 A079460

KEYWORD

more,nonn

AUTHOR

Jim Nastos, Jan 13 2003

EXTENSIONS

a(10)-a(12) added using tinygraph by Falk Hüffner, Jan 15 2016

STATUS

approved