Triangle T(n,k) read by rows; related to number of preorders.

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =5a(5) =5a(6) =1a(7) =10a(8) =24a(9) =16a(10) =1a(11) =18a(12) =79a(13) =122a(14) =61a(15) =1a(16) =31a(17) =223a(18) =602a(19) =680a(20) =272a(21) =1a(22) =52a(23) =579a(24) =2439a(25) =4682a(26) =4155a(27) =1385a(28) =1a(29) =86