Triangle read by rows: Number of crossing set partitions of {1,2,...,n} into k blocks.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =1a(8) =0a(9) =0a(10) =0a(11) =5a(12) =5a(13) =0a(14) =0a(15) =0a(16) =16a(17) =40a(18) =15a(19) =0a(20) =0a(21) =0a(22) =42a(23) =196a(24) =175a(25) =35a(26) =0a(27) =0a(28) =0a(29) =99