Primes dividing terms of A128685.

Terms

a(0) =13a(1) =79a(2) =4057a(3) =36037a(4) =222379a(5) =973597a(6) =1310611a(7) =2070433a(8) =4381183a(9) =4905427a(10) =8145943651a(11) =21843304081a(12) =66988402183