A176142 Number of nonequivalent monoids of order n in which the action of the unit group on the maximal ideal is nontrivial.

0, 0, 0, 2, 5, 58, 428, 5539, 101082, 9269715

Offset: 1

Author

Andreas Distler, Apr 10 2010

Keywords

• hard
• nonn

Comments

Monoids are considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).

The invertible elements form the unit group of the monoid, all remaining elements form the maximal ideal.

Links

• A. Distler and T. W. Kelsey, The Monoids of Orders Eight, Nine & Ten, Annals of Mathematics and Artificial Intelligence, 56 (2009), 3-25.

Crossrefs

Cf. A058133, A151823