Number of semigroups of order n with 3 idempotents, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).
A005591
Number of semigroups of order n with 3 idempotents, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).
Terms
- a(0) =6a(1) =44a(2) =351a(3) =3093a(4) =33445a(5) =600027a(6) =68769167a(7) =219587421825
External references
- oeis: A005591