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

Author

Travis Hoppe and Anna Petrone, May 22 2014

Keywords

• nonn
• more

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

• 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)

Extensions

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