Number of nonisomorphic semigroups with n elements and empty center.
A391160
Number of nonisomorphic semigroups with n elements and empty center.
Terms
- a(0) =1a(1) =0a(2) =2a(3) =6a(4) =55a(5) =552a(6) =7954a(7) =143958
External references
- oeis: A391160