a(n) = (6^n/n!) * Product_{k=0..n-1} ( 6*k + 11 ).

A004998

a(n) = (6^n/n!) * Product_{k=0..n-1} ( 6*k + 11 ).

Terms

    a(0) =1a(1) =66a(2) =3366a(3) =154836a(4) =6735366a(5) =282885372a(6) =11598300252a(7) =467245810152

External references