Primes with minimal digit = 7.

Terms

a(0) =7a(1) =79a(2) =97a(3) =787a(4) =797a(5) =877a(6) =887a(7) =977a(8) =997a(9) =7789a(10) =7877a(11) =7879a(12) =8779a(13) =8887a(14) =9787a(15) =9887a(16) =77797a(17) =77899a(18) =77977a(19) =77999a(20) =78779a(21) =78787a(22) =78797a(23) =78877a(24) =78887a(25) =78889a(26) =78977a(27) =78979a(28) =78989a(29) =79777