Triangle T(n,k) of k-block ordered bicoverings of an unlabeled n-set, n >= 2, k = 3..n+floor(n/2).

Terms

a(0) =3a(1) =7a(2) =16a(3) =12a(4) =63a(5) =125a(6) =90a(7) =18a(8) =162a(9) =722a(10) =1716a(11) =1680a(12) =25a(13) =341a(14) =2565a(15) =11350a(16) =27342a(17) =29960a(18) =7560a(19) =33a(20) =636a(21) =7180a(22) =49860a(23) =208302a(24) =503000a(25) =631512a(26) =302400a(27) =42a(28) =1092a(29) =17335