%I #6 Mar 30 2012 17:37:11
%S 1,2,5,16,62,342,3435
%N Number of commutative semigroups of order n with 1 idempotent.
%H <a href="/index/Se#semigroups">Index entries for sequences related to semigroups</a>
%Y Column 1 of A058116.
%K nonn,hard
%O 1,2
%A _Christian G. Bower_, Nov 09 2000