a(n) is the least prime factor of (9 * 10^(6*n-4) - 11) / 7.

Terms

a(0) =127a(1) =401a(2) =19a(3) =53a(4) =151a(5) =7a(6) =139a(7) =127a(8) =19a(9) =78721a(10) =3458771a(11) =19a(12) =7a(13) =38954263a(14) =19a(15) =79a(16) =53a(17) =19a(18) =157a(19) =7a(20) =19a(21) =127a(22) =18191a(23) =19a(24) =12119a(25) =421a(26) =7a(28) =79a(29) =19