Triangle of a(n,k) = number of k-member minimal covers of an n-set (n >= k >= 1).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =6a(5) =1a(6) =1a(7) =25a(8) =22a(9) =1a(10) =1a(11) =90a(12) =305a(13) =65a(14) =1a(15) =1a(16) =301a(17) =3410a(18) =2540a(19) =171a(20) =1a(21) =1a(22) =966a(23) =33621a(24) =77350a(25) =17066a(26) =420a(27) =1a(28) =1a(29) =3025