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Number of unlabeled, connected graphs on n vertices that have no induced subgraph isomorphic to a gem, where a gem is a 4-path with a fifth vertex adjacent to all four of the vertices in the path.
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%I #11 Jan 10 2022 11:55:03

%S 1,1,2,6,20,93,534,4291,47120,739310,16641941,539386425

%N Number of unlabeled, connected graphs on n vertices that have no induced subgraph isomorphic to a gem, where a gem is a 4-path with a fifth vertex adjacent to all four of the vertices in the path.

%D A. Brandstadt and D. Kratsch, "On (P5,Gem)-free and (P5,Gem,co-Gem)-free Graphs: Structure and algorithmic applications," Manuscript 2000.

%H Qingqiong Cai, Jan Goedgebeur, and Shenwei Huang, <a href="https://arxiv.org/abs/2108.05492">Some Results on k-Critical P_5-Free Graphs</a>, arXiv:2108.05492 [math.CO], 2021.

%H F. Hüffner, <a href="https://github.com/falk-hueffner/tinygraph">tinygraph</a>, software for generating integer sequences based on graph properties, version e8699da.

%K more,nonn

%O 1,3

%A _Jim Nastos_, Jan 24 2003

%E a(10)-a(12) added using tinygraph by _Falk Hüffner_, Jan 17 2016