Triangle read by rows: T(n, k) = (-1)^k*Product_{j=0..k-1} (j - n)*(j + n), for 0 <= k <= n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =12a(6) =1a(7) =9a(8) =72a(9) =360a(10) =1a(11) =16a(12) =240a(13) =2880a(14) =20160a(15) =1a(16) =25a(17) =600a(18) =12600a(19) =201600a(20) =1814400a(21) =1a(22) =36a(23) =1260a(24) =40320a(25) =1088640a(26) =21772800a(27) =239500800a(28) =1a(29) =49