Commutative Nil Semigroups

• All subdirectly irreducible commutative nil semigroups with 3 elements 1
• All subdirectly irreducible commutative nil semigroups with 4 elements 4
• All subdirectly irreducible commutative nil semigroups with 5 elements 12
• All subdirectly irreducible commutative nil semigroups with 6 elements 68