Triangle T(n,k) of numbers of proper k-covers of an unlabeled n-set, k=1..2^n-2.

Terms

a(0) =0a(1) =1a(2) =0a(3) =2a(4) =5a(5) =4a(6) =2a(7) =1a(8) =0a(9) =4a(10) =19a(11) =58a(12) =113a(13) =168a(14) =193a(15) =171a(16) =119a(17) =68a(18) =29a(19) =10a(20) =3a(21) =1a(22) =0a(23) =6a(24) =53a(25) =325a(26) =1551a(27) =6007a(28) =19533a(29) =54119