Number of ways of placing non-attacking knights on an n X n chessboard symmetric under 90-degree rotation.

A130728

Number of ways of placing non-attacking knights on an n X n chessboard symmetric under 90-degree rotation.

Terms

    a(0) =1a(1) =2a(2) =2a(3) =6a(4) =3a(5) =27a(6) =28a(7) =324a(8) =338a(9) =5991a(10) =6875a(11) =228512a(12) =322056a(13) =17782554a(14) =30487207a(15) =2704389848a(16) =5451449965a(17) =819155081866

External references