Number of ways to place 3n rooks on an n X n board, 3 rooks in each row and each column, multiple rooks in an allowed cell, and exactly 4 rooks below the main diagonal.
A260583
Number of ways to place 3n rooks on an n X n board, 3 rooks in each row and each column, multiple rooks in an allowed cell, and exactly 4 rooks below the main diagonal.
Terms
- a(0) =11a(1) =595a(2) =14679a(3) =253247a(4) =3564803a(5) =44226950a(6) =505572550a(7) =5473391465a(8) =57122380066a(9) =581477852342
External references
- oeis: A260583