A058133 Number of monoids (semigroups with identity) of order n, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).
0, 1, 2, 6, 27, 156, 1373, 17730, 858977, 1844075697, 52991253973742
Offset: 0
Links
- Eric Postpischil Posting to sci.math newsgroup, May 21 1990
- Andreas Distler and Tom Kelsey, The Monoids of Order Eight and Nine. Lecture Notes in Computer Science 5144 (2008), 61-76.
- Andreas Distler and Tom Kelsey, The Monoids of Orders Eight, Nine & Ten. Annals of Mathematics and Artificial Intelligence 56 (2009), 3-25.
- Index entries for sequences related to monoids
Extensions
a(8) and a(9) from Distler & Kelsey (2008), added by N. J. A. Sloane, Jul 10 2009
a(10) from Distler & Kelsey (2009), added by Max Alekseyev, Jul 13 2009
a(0) prepended by Jianing Song, Oct 26 2019