Array A(n,k) = n*A(n,k-1) + A(n,k-2) read by upward antidiagonals, starting A(n,0) = 0, A(n,1) = 1.

Terms

a(0) =0a(1) =0a(2) =1a(3) =0a(4) =1a(5) =1a(6) =0a(7) =1a(8) =2a(9) =2a(10) =0a(11) =1a(12) =3a(13) =5a(14) =3a(15) =0a(16) =1a(17) =4a(18) =10a(19) =12a(20) =5a(21) =0a(22) =1a(23) =5a(24) =17a(25) =33a(26) =29a(27) =8a(28) =0a(29) =1