A123425 Number of HHD-free graphs on n nodes.

1, 2, 4, 11, 32, 128, 608, 3689, 27238, 244922, 2659678, 35013106, 562450090

Offset

1,2

Comments

A graph is called HHD-free if it does not contain a house, a hole of length at least five or a domino as an induced subgraph. All HHD-free graphs are perfect. - Falk Hüffner, Jul 01 2018

Links

Table of n, a(n) for n=1..13.

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: A123418 A123412 A074408 * A123414 A123410 A123434

Adjacent sequences: A123422 A123423 A123424 * A123426 A123427 A123428

Keyword

nonn,more

Author

N. J. A. Sloane, Oct 18 2006

Extensions

a(11)-a(13) added using tinygraph by Falk Hüffner, Jul 01 2018

Status

approved