Number of semigroups of order n, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).
A001423
Number of semigroups of order n, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).
Terms
- a(0) =1a(1) =1a(2) =4a(3) =18a(4) =126a(5) =1160a(6) =15973a(7) =836021a(8) =1843120128
External references
- oeis: A001423