Number of nonisomorphic semigroups of order n minus number of groups of order n.

A186117

Number of nonisomorphic semigroups of order n minus number of groups of order n.

Terms

    a(0) =0a(1) =4a(2) =23a(3) =186a(4) =1914a(5) =28632a(6) =1627671a(7) =3684030412

External references