A123426 Number of Hoang perfect graphs on n nodes.

1, 2, 4, 11, 33, 145, 848, 7111, 77067, 1007506, 15150150, 259469001

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