n! times the number of posets with n unlabeled elements.

A363911

n! times the number of posets with n unlabeled elements.

Terms

    a(0) =1a(1) =1a(2) =4a(3) =30a(4) =384a(5) =7560a(6) =228960a(7) =10306800a(8) =685399680a(9) =66490865280

External references