Triangle read by rows: T(n,k) number of arrangements of non-attacking rooks on an n X n right triangular board where the top rook is in row k (n >= 0, 1 <= k <= n+1).
A259691
Triangle read by rows: T(n,k) number of arrangements of non-attacking rooks on an n X n right triangular board where the top rook is in row k (n >= 0, 1 <= k <= n+1).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =2a(5) =1a(6) =5a(7) =6a(8) =3a(9) =1a(10) =15a(11) =20a(12) =12a(13) =4a(14) =1a(15) =52a(16) =74a(17) =51a(18) =20a(19) =5a(20) =1a(21) =203a(22) =302a(23) =231a(24) =104a(25) =30a(26) =6a(27) =1a(28) =877a(29) =1348
External references
- oeis: A259691