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Number of simple graphs with n vertices which contain no K4 subgraph.
3

%I #11 May 08 2018 03:56:28

%S 1,2,4,10,29,120,685,6431,103164,2894632,138892304,11118977705,

%T 1459412127955

%N Number of simple graphs with n vertices which contain no K4 subgraph.

%C The graphs do not need to be connected.

%F a(n) = 1+A052450(n)+A052451(n).

%Y Cf. A000088, A006785 (no K3), A115196 (graphs by clique number), A304125 (no K5).

%K nonn,more

%O 1,2

%A _Brendan McKay_, May 06 2018

%E a(13) from _Brendan McKay_, May 08 2018