Number of commutative asymmetric semigroups of order n.

A058105

Number of commutative asymmetric semigroups of order n.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =9a(4) =39a(5) =201a(6) =1258a(7) =10013a(8) =142755

External references