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Number of 4-connected unlabeled n-node graphs.
9

%I #53 Sep 04 2019 17:12:26

%S 0,0,0,0,1,4,25,384,14480,1211735,184649399

%N Number of 4-connected unlabeled n-node graphs.

%C The definition means that the connectivity is 4 or more.

%H T. Hoppe and A. Petrone, <a href="http://arxiv.org/abs/1408.3644">Integer sequence discovery from small graphs</a>, arXiv preprint arXiv:1408.3644, [math.CO], 2014.

%H T. Hoppe and A. Petrone, <a href="http://doi.org/10.1016/j.dam.2015.07.017">Integer sequence discovery from small graphs</a>, Discr. Appl. Math. 201 (2016) 172-181.

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

%F a(n) = A086217(n) + A052445(n). - _Andrew Howroyd_, Sep 04 2019

%e There are 4 different 4-connected graphs on 6 vertices. - _Dylan Thurston_, Jun 18 2009

%Y See A052445 for exactly-4-connected graphs.

%Y See A086217 for 5-connected graphs.

%Y See A259862 for further information.

%K nonn,hard,more

%O 1,6

%A _Eric W. Weisstein_, Jul 12 2003

%E Offset corrected by _Dylan Thurston_, Jun 18 2009

%E a(10) from the Encyclopedia of Finite Graphs (_Travis Hoppe_ and Anna Petrone), Apr 11 2014

%E Minor edits by _N. J. A. Sloane_, Jul 08 2015 at the suggestion of _Brendan McKay_.