Number of ways of placing kings with no more than 1 mutual attack on an n X n chessboard symmetric about main diagonal.

A143872

Number of ways of placing kings with no more than 1 mutual attack on an n X n chessboard symmetric about main diagonal.

Terms

    a(0) =1a(1) =2a(2) =5a(3) =15a(4) =62a(5) =329a(6) =2307a(7) =21482a(8) =264021a(9) =4334045a(10) =94435970a(11) =2750500857a(12) =106769182533

External references