Primes having only {3, 7, 9} as digits.

Terms

a(0) =3a(1) =7a(2) =37a(3) =73a(4) =79a(5) =97a(6) =337a(7) =373a(8) =379a(9) =397a(10) =733a(11) =739a(12) =773a(13) =797a(14) =937a(15) =977a(16) =997a(17) =3373a(18) =3733a(19) =3739a(20) =3779a(21) =3793a(22) =3797a(23) =7333a(24) =7393a(25) =7793a(26) =7933a(27) =7937a(28) =7993a(29) =9337