Triangle read by rows: T(n,k) is the number of labeled tiered posets with n elements and height k.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =1a(5) =2a(6) =0a(7) =1a(8) =6a(9) =6a(10) =0a(11) =1a(12) =50a(13) =36a(14) =24a(15) =0a(16) =1a(17) =510a(18) =510a(19) =240a(20) =120a(21) =0a(22) =1a(23) =7682a(24) =10620a(25) =4800a(26) =1800a(27) =720a(28) =0a(29) =1