

A058129


Number of monoids (semigroups with identity) of order n.


14




OFFSET

0,3


LINKS

Table of n, a(n) for n=0..8.
Remigiusz Durka, Kamil Grela, On the number of possible resonant algebras, arXiv:1911.12814 [hepth], 2019.
Eric Postpischil, Posting to sci.math newsgroup, May 21 1990
Clayton Cristiano Silva, Irreducible Numerical Semigroups, University of Campinas, São Paulo, Brazil (2019).
Index entries for sequences related to monoids


FORMULA

a(n) = 2*A058133(n)  A058132(n).
a(n) < A027851(n) except for equality iff n = 1.  M. F. Hasler, Dec 10 2018


CROSSREFS

Cf. A058132, A058133.
Cf. A027851 (number of all nonisomorphic semigroups).
Sequence in context: A014307 A000154 A003713 * A101514 A247240 A266356
Adjacent sequences: A058126 A058127 A058128 * A058130 A058131 A058132


KEYWORD

nonn,hard,more


AUTHOR

Christian G. Bower, Nov 13 2000


EXTENSIONS

a(8) from Christian G. Bower, Dec 26 2006
a(0) = 0 prepended by M. F. Hasler, Dec 10 2018


STATUS

approved



