Triangle read by rows: number of set partitions of n elements with k connectors, 0<=k<n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =1a(6) =1a(7) =7a(8) =6a(9) =1a(10) =1a(11) =16a(12) =24a(13) =10a(14) =1a(15) =1a(16) =39a(17) =86a(18) =61a(19) =15a(20) =1a(21) =1a(22) =105a(23) =307a(24) =313a(25) =129a(26) =21a(27) =1a(28) =1a(29) =314