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

A038020

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

Terms

    a(0) =0a(1) =0a(2) =0a(3) =2a(4) =0a(5) =2a(6) =9a(7) =54a(8) =0a(9) =30a(10) =15376a(11) =12664a(12) =14304a(13) =4096a(14) =3187

External references