%I #5 Oct 20 2014 18:32:24
%S 1,2,5,17,92,581,4989,54250,776877,14503255,356467268,11553201879,
%T 495106836021
%N Number of ways of placing kings with no more than 2 mutual attacks on an n X n chessboard symmetric about main diagonal.
%K nonn,more,hard
%O 0,2
%A _R. H. Hardin_, Sep 04 2008