Triangle T(n, k) = Sum_{i=1..n} Stirling2(n,i) * abs(Stirling1(i-1,k-1)), n >= 1, 1 <= k <= n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =1a(6) =1a(7) =15a(8) =9a(9) =1a(10) =1a(11) =66a(12) =66a(13) =16a(14) =1a(15) =1a(16) =365a(17) =500a(18) =190a(19) =25a(20) =1a(21) =1a(22) =2528a(23) =4215a(24) =2150a(25) =435a(26) =36a(27) =1a(28) =1a(29) =21259