Triangle read by rows: T(n,k) is the number of groupoids with n elements and k idempotents.

A038018

Triangle read by rows: T(n,k) is the number of groupoids with n elements and k idempotents.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =3a(4) =4a(5) =3a(6) =978a(7) =1485a(8) =729a(9) =138a(10) =56630832a(11) =75503872a(12) =37755904a(13) =8390656a(14) =700688a(20) =794734575200

External references