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A151823 Number of nonequivalent monoids of order n with more than one invertible element 3
0, 1, 2, 9, 30, 213, 1757, 22956, 955569, 1853259264 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) is also the number of nonequivalent monoids with nontrivial unit group. [From Tom Kelsey (tom(AT)cs.st-and.ac.uk), Apr 01 2010]

LINKS

Table of n, a(n) for n=1..10.

Andreas Distler and Tom Kelsey, The Monoids of Order Eight and Nine, in: Intelligent Computer Mathematics, Lecture Notes in Computer Science, Volume 5144/2008, pp. 61-76, Springer-Verlag.

Andreas Distler and Tom Kelsey, The Monoids of Orders Eight, Nine & Ten, Annals of Mathematics and Artificial Intelligence, 56 (2009), 3-25. [From Tom Kelsey (tom(AT)cs.st-and.ac.uk), Apr 01 2010]

CROSSREFS

Cf. A001423, A058133.

Sequence in context: A343565 A318101 A347893 * A084652 A188776 A261443

Adjacent sequences:  A151820 A151821 A151822 * A151824 A151825 A151826

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Jul 10 2009

EXTENSIONS

Definition corrected by Tom Kelsey (tom(AT)cs.st-andrews.ac.uk), Apr 01 2010

Corrected and extended by Tom Kelsey (tom(AT)cs.st-and.ac.uk), Apr 01 2010

STATUS

approved

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Last modified May 29 05:00 EDT 2022. Contains 354122 sequences. (Running on oeis4.)