Number of isomorphism classes of idempotent semigroups of order n.

A058112

Number of isomorphism classes of idempotent semigroups of order n.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =10a(4) =46a(5) =251a(6) =1682a(7) =13213a(8) =119826a(9) =1228712

External references