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A123426 Number of Hoang perfect graphs on n nodes. 0
1, 2, 4, 11, 33, 145, 848, 7111, 77067, 1007506, 15150150, 259469001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

A graph is called Hoang if its wing graph is bipartite. The wing graph W(G) of a graph G has as its vertices the edges of G and two edges are adjacent in W(G) if there is an induced P4 in G that has these two edges as its ends. - Falk Hüffner, Jun 30 2018

LINKS

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

S. Hougardy, Classes of perfect graphs, Discr. Math. 306 (2006), 2529-2571.

F. Hüffner, tinygraph, software for generating integer sequences based on graph properties, version 6c1dbe4.

CROSSREFS

Sequence in context: A123453 A351157 A123459 * A277204 A123437 A123435

Adjacent sequences: A123423 A123424 A123425 * A123427 A123428 A123429

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Oct 18 2006

EXTENSIONS

a(11)-a(12) added using tinygraph by Falk Hüffner, Jun 30 2018

STATUS

approved

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Last modified December 4 21:02 EST 2022. Contains 358570 sequences. (Running on oeis4.)