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A058168 Triangle: Number of asymmetric commutative semigroups of order n with k idempotents. 1

%I

%S 1,2,1,3,5,1,7,18,12,2,24,65,73,34,5,133,276,399,309,123,18,1722,1595,

%T 2240,2331,1500,544,81

%N Triangle: Number of asymmetric commutative semigroups of order n with k idempotents.

%H <a href="/index/Se#semigroups">Index entries for sequences related to semigroups</a>

%e 1; 2,1; 3,5,1; 7,18,12,2; 24,65,73,34,5; ...

%Y Row sums give A058105.

%K nonn,tabl,hard

%O 1,2

%A _Christian G. Bower_, Nov 19 2000

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Last modified February 20 15:02 EST 2019. Contains 320327 sequences. (Running on oeis4.)