Smallest nonempty set S containing prime divisors of 10k+1 for each k in S.

Terms

a(0) =3a(1) =7a(2) =11a(3) =13a(4) =17a(5) =19a(6) =23a(7) =29a(8) =31a(9) =37a(10) =43a(11) =47a(12) =53a(13) =59a(14) =61a(15) =71a(16) =73a(17) =79a(18) =83a(19) =97a(20) =107a(21) =113a(22) =131a(23) =139a(24) =157a(25) =163a(26) =191a(27) =197a(28) =233a(29) =277