%I #12 Sep 29 2019 07:05:56
%S 0,0,0,0,0,0,0,1,0,2,2,3,4,9,6,15,14,21,22,37,30,53,52,69,74,102,96
%N Rectilinear crossing number A014540(n) - crossing number A000241(n) of complete graph on n nodes.
%e For 8 nodes the crossing number is 18 and the rectilinear crossing number is 19. The difference for 8 nodes is 1. Thus a(8)=1.
%Y Cf. A000241, A014540, A028723.
%K nonn,hard,more
%O 1,10
%A _Ed Pegg Jr_, May 03 2019