Primes that contain digits 7 and 8 only.

Terms

a(0) =7a(1) =787a(2) =877a(3) =887a(4) =7877a(5) =8887a(6) =78787a(7) =78877a(8) =78887a(9) =87877a(10) =87887a(11) =777787a(12) =777877a(13) =778777a(14) =787777a(15) =878777a(16) =888887a(17) =7778777a(18) =7788787a(19) =7877777a(20) =7878877a(21) =7878887a(22) =7888877a(23) =8787887a(24) =8788777a(25) =8877787a(26) =8887777a(27) =77778887a(28) =77787887a(29) =77877887