Triangle read by rows: T(n,k) = binomial(n,k)*(n-1)!/(k-1)!.

Terms

a(0) =1a(1) =2a(2) =1a(3) =6a(4) =6a(5) =1a(6) =24a(7) =36a(8) =12a(9) =1a(10) =120a(11) =240a(12) =120a(13) =20a(14) =1a(15) =720a(16) =1800a(17) =1200a(18) =300a(19) =30a(20) =1a(21) =5040a(22) =15120a(23) =12600a(24) =4200a(25) =630a(26) =42a(27) =1a(28) =40320a(29) =141120