Sum of the divisors of 7^n+1.

Terms

a(0) =3a(1) =15a(2) =93a(3) =660a(4) =3606a(5) =34560a(6) =236964a(7) =1559520a(8) =9155916a(9) =77423280a(10) =530807472a(11) =3868683120a(12) =21224771760a(13) =185094572580