%I #5 Oct 20 2014 18:34:37
%S 1,2,3,15,52,383,2273,28764,295391,6544311,116636234
%N Number of ways of placing kings with no more than 3 mutual attacks on an n X n chessboard symmetric under 180 degree rotation.
%K nonn,more,hard
%O 0,2
%A _R. H. Hardin_, Sep 04 2008