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%I #14 Dec 08 2015 09:24:54
%S 1,2,6,23,109,630,4329,34458
%N Number of nonisomorphic n-element left regular bands.
%C Computed by Evan Chen for n<7 using Sage 6.9 and Yongyi Chen for n<9 using Python.
%H K. S. Brown, <a href="http://arxiv.org/abs/math/0006145">Semigroups, rings, and Markov chains</a>, arXiv:math/0006145 [math.PR], 2000.
%H K. S. Brown, <a href="http://dx.doi.org/10.1023/A:1007822931408">Semigroups, rings, and Markov chains</a>, J. Theoretical Prob. 13 (2000), 871-938.
%e For n=2 the two LRBs have elements x,y and relations (1) x^2=xy=yx=x, y^2=y, (2) y^2=xy=y, x^2=yx=x.
%K nonn,more
%O 1,2
%A _Richard Stanley_, Nov 27 2015
%E a(7)-a(8) from Yongyi Chen entered by _Richard Stanley_, Nov 30 2015
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