Triangle read by rows: T(n, k) = (n - k)!*(n + k)!/n!.

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =3a(5) =12a(6) =6a(7) =8a(8) =20a(9) =120a(10) =24a(11) =30a(12) =60a(13) =210a(14) =1680a(15) =120a(16) =144a(17) =252a(18) =672a(19) =3024a(20) =30240a(21) =720a(22) =840a(23) =1344a(24) =3024a(25) =10080a(26) =55440a(27) =665280a(28) =5040a(29) =5760