%I #27 Jun 22 2021 08:35:46
%S 1,1,2,5,16,63,313,2014,16724,178608,2422046,41049952,855470220
%N Number of unlabeled, connected graphs on n vertices which have no induced subgraph isomorphic to a C4 (cycle on 4 vertices.)
%C Different from A345673.
%H Z. Blázsik, M. Hujter, M. Pluhár and Z. Tuza, <a href="http://dx.doi.org/10.1016/0012-365X(93)90477-B">Graphs with no C4 and 2K2</a>, Discrete Math. 115 (1993) 51-55.
%H Uli Fahrenberg, Christian Johansen, Georg Struth, Ratan Bahadur Thapa, <a href="https://arxiv.org/abs/1910.06162">Generating Posets Beyond N</a>, arXiv:1910.06162 [cs.FL], 2019.
%H Uli Fahrenberg, Christian Johansen, Georg Struth, Krzysztof Ziemiański, <a href="https://arxiv.org/abs/2106.10895">Posets with Interfaces for Concurrent Kleene Algebra</a>, arxiv:2106.10895 [cs.FL], 2021.
%Y Cf. A345673.
%K more,nonn
%O 1,3
%A _Jim Nastos_, Jan 24 2003
%E More terms from _Falk Hüffner_, Jan 11 2016, computed using https://github.com/falk-hueffner/tinygraph (nauty based) version 8489dde