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Number of connected open-bowtie-free graphs on n nodes.
9

%I #15 Jan 16 2016 12:01:44

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

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

%C 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.

%C O-\ /-O

%C O |

%C O-/ \-O

%H Travis Hoppe and Anna Petrone, <a href="https://github.com/thoppe/Encyclopedia-of-Finite-Graphs">Encyclopedia of Finite Graphs</a>

%H F. Hüffner, <a href="https://github.com/falk-hueffner/tinygraph">tinygraph</a>, software for generating integer sequences based on graph properties, version 231ba55

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/BullGraph.html">Bull Graph</a>

%Y Cf. A079575 (bull-free graphs)

%K nonn,more

%O 1,3

%A _Travis Hoppe_ and _Anna Petrone_, May 22 2014

%E a(11)-a(13) added using tinygraph by _Falk Hüffner_, Jan 16 2016