Search: id:A058133
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%I A058133
%S A058133 1,2,6,27,156,1373,17730,858977,1844075697,52991253973742
%N 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).
%D A058133 Andreas Distler and Tom Kelsey, The Monoids of Order Eight and Nine, 
               in Intelligent Computer Mathematics, Lecture Notes in Computer Science, 
               Volume 5144/2008, Springer-Verlag. [From N. J. A. Sloane, Jul 10 
               2009]
%H A058133 Eric Postpischil <a href="http://groups.google.com/groups?&hl=en&lr=&ie=UTF-8&selm=11802%40shlump.nac.dec.com\
               &rnum=2">Posting to sci.math newsgroup, May 21 1990</a>
%H A058133 <a href="Sindx_Mo.html#monoids">Index entries for sequences related to 
               monoids</a>
%H A058133 A Distler, T Kelsey. <a href="http://www-circa.mcs.st-and.ac.uk/Preprints/
               monoids10.pdf">The Monoids of Orders Eight, Nine & Ten</a>. preprint. 
               [From Max Alekseyev (maxale(AT)gmail.com), Jul 13 2009]
%Y A058133 a(n)=(A058129(n)+A058132(n))/2.
%Y A058133 Cf. A001423, A151823.
%Y A058133 Sequence in context: A030858 A030932 A118192 this_sequence A009308 A032186 
               A122938
%Y A058133 Adjacent sequences: A058130 A058131 A058132 this_sequence A058134 A058135 
               A058136
%K A058133 nonn,more,hard
%O A058133 1,2
%A A058133 Christian G. Bower (bowerc(AT)usa.net), Nov 13 2000
%E A058133 a(8) and a(9) from the Distler-Kelsey paper [N. J. A. Sloane, Jul 10 
               2009]
%E A058133 a(10) from the Distler-Kelsey preprint. Max Alekseyev (maxale(AT)gmail.com), 
               Jul 13 2009

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