Number of hierarchical orderings ("societies") of n labeled elements ("individuals") with at least two occupied levels.

A097237

Number of hierarchical orderings ("societies") of n labeled elements ("individuals") with at least two occupied levels.

Terms

    a(0) =0a(1) =2a(2) =12a(3) =86a(4) =780a(5) =8462a(6) =106092a(7) =1507046a(8) =23905740a(9) =418581662a(10) =8014481772a(11) =166501716086

External references