Number of nonequivalent ways to place 2n nonattacking kings on a 4 X 2n chessboard under all symmetry operations of the rectangle.
A321614
Number of nonequivalent ways to place 2n nonattacking kings on a 4 X 2n chessboard under all symmetry operations of the rectangle.
Terms
- a(0) =1a(1) =4a(2) =23a(3) =106a(4) =473a(5) =1939a(6) =7618a(7) =28703a(8) =105112a(9) =375597a(10) =1316944a(11) =4544124a(12) =15474559a(13) =52108212a(14) =173799309a(15) =574908646a(16) =1888125243a(17) =6162032375a(18) =19998659760a(19) =64584817367a(20) =207655073310a(21) =665017743665
External references
- oeis: A321614