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A038020 Triangle: T(n,k), k<=n: groupoids with a nontrivial symmetry with n elements and k idempotents. 0

%I

%S 0,0,0,2,0,2,9,54,0,30,15376,12664,14304,4096,3187

%N Triangle: T(n,k), k<=n: groupoids with a nontrivial symmetry with n elements and k idempotents.

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

%F Difference of A038018 and A038019.

%Y Cf. A001329, A030248, A030251, A030271.

%K nonn,tabl

%O 0,4

%A _Christian G. Bower_, May 15 1998

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Last modified August 10 04:49 EDT 2022. Contains 356029 sequences. (Running on oeis4.)