A143874 - OEIS

A143874

Number of ways of placing kings with no more than 1 mutual attack on an n X n chessboard symmetric under 180 degree rotation.

%I #5 Oct 20 2014 18:31:02

%S 1,2,3,7,18,111,497,4630,38327,702227,10398834

%N Number of ways of placing kings with no more than 1 mutual attack 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