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%I #10 Feb 17 2022 14:19:44
%S 1,1,3,10,46,251,1682,13213,119826,1228712
%N Number of isomorphism classes of idempotent semigroups of order n.
%H <a href="/index/Mo#monoids">Index entries for sequences related to monoids</a>
%H <a href="/index/Se#semigroups">Index entries for sequences related to semigroups</a>
%Y Main diagonal of A058108 and A058137.
%Y Cf. A027851, A351730 (labeled).
%K nonn,hard
%O 0,3
%A _Christian G. Bower_, Nov 09 2000
%E Updated Feb 19 2001
%E a(8)-a(9) added by _Andrew Howroyd_, Feb 17 2022