A242791 Number of connected open-bowtie-free graphs on n nodes.

1, 1, 2, 6, 11, 34, 98, 408, 1957, 12740, 108649, 1281776, 20787104

Offset

1,3

Comments

An open-bowtie graph (also known as cricket) is the graph formed by connecting two bridges, each with a single vertex to the same vertex of C3 (the cycle graph with three vertices). It is chromatically equivalent to the bull graph.

O-\ /-O

O |

O-/ \-O

Links

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

Travis Hoppe and Anna Petrone, Encyclopedia of Finite Graphs

F. Hüffner, tinygraph, software for generating integer sequences based on graph properties, version 231ba55

Eric Weisstein's World of Mathematics, Bull Graph

Crossrefs

Cf. A079575 (bull-free graphs)

Sequence in context: A026564 A243794 A318199 * A156065 A302749 A130274

Adjacent sequences: A242788 A242789 A242790 * A242792 A242793 A242794

Keyword

nonn,more

Author

Travis Hoppe and Anna Petrone, May 22 2014

Extensions

a(11)-a(13) added using tinygraph by Falk Hüffner, Jan 16 2016

Status

approved