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%I #25 Sep 07 2018 03:55:24
%S 0,1,1,3,10,54,407,4630,68425,1211637
%N Number of nonisomorphic 2-connected circle graphs of order n.
%H L. E. Danielsen, <a href="http://www.ii.uib.no/~larsed/circle/">Database of Circle Graphs</a>
%H L. E. Danielsen and M. G. Parker, <a href="https://arxiv.org/abs/0804.2576">Interlace polynomials: Enumeration, unimodality, and connections to codes</a>, arXiv:0804.2576 [math.CO], 2008-2009.
%H L. E. Danielsen and M. G. Parker, <a href="https://doi.org/10.1016/j.dam.2009.11.011">Interlace polynomials: Enumeration, unimodality, and connections to codes</a>, Discrete Appl. Math. 158(6), pp. 636-648, 2010.
%e The 3 circle graphs with n = 4 vertices which are 2-connected are K_4, the square and the square with one diagonal.
%Y Cf. A156809, A156808, A002218.
%K nonn,hard,more
%O 1,4
%A _Fidel I. Schaposnik_, Sep 01 2018