Primes of form 10n+7.

Terms

a(0) =7a(1) =17a(2) =37a(3) =47a(4) =67a(5) =97a(6) =107a(7) =127a(8) =137a(9) =157a(10) =167a(11) =197a(12) =227a(13) =257a(14) =277a(15) =307a(16) =317a(17) =337a(18) =347a(19) =367a(20) =397a(21) =457a(22) =467a(23) =487a(24) =547a(25) =557a(26) =577a(27) =587a(28) =607a(29) =617