Number of 3-antichain covers of a labeled n-set.

Terms

a(0) =0a(1) =0a(2) =0a(3) =2a(4) =56a(5) =790a(6) =8380a(7) =76482a(8) =638736a(9) =5043950a(10) =38390660a(11) =285007162a(12) =2079779416a(13) =14995363110a(14) =107204473740a(15) =761823557042