Number of ways to place m nonattacking queens on an m X n board, 1 <= m <= n (triangular array).

Terms

a(0) =1a(1) =2a(2) =0a(3) =3a(4) =2a(5) =0a(6) =4a(7) =6a(8) =4a(9) =2a(10) =5a(11) =12a(12) =14a(13) =12a(14) =10a(15) =6a(16) =20a(17) =36a(18) =46a(19) =40a(20) =4a(21) =7a(22) =30a(23) =76a(24) =140a(25) =164a(26) =94a(27) =40a(28) =8a(29) =42