Square array A(n,k), n >= 0, k >= 1, read by antidiagonals: A(n,k) = Product_{j=1..n} (k^j - 1).

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =1a(5) =0a(6) =1a(7) =2a(8) =3a(9) =0a(10) =1a(11) =3a(12) =16a(13) =21a(14) =0a(15) =1a(16) =4a(17) =45a(18) =416a(19) =315a(20) =0a(21) =1a(22) =5a(23) =96a(24) =2835a(25) =33280a(26) =9765a(27) =0a(28) =1a(29) =6