Number of monoids (semigroups with identity) of order n, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).

A058133

Number of monoids (semigroups with identity) of order n, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).

Terms

    a(0) =0a(1) =1a(2) =2a(3) =6a(4) =27a(5) =156a(6) =1373a(7) =17730a(8) =858977a(9) =1844075697

External references