Primes that contain only the digits (2, 5, 7).

Terms

a(0) =2a(1) =5a(2) =7a(3) =227a(4) =257a(5) =277a(6) =557a(7) =577a(8) =727a(9) =757a(10) =2557a(11) =2777a(12) =5227a(13) =5527a(14) =5557a(15) =7577a(16) =7727a(17) =7757a(18) =22277a(19) =22727a(20) =22777a(21) =25577a(22) =27277a(23) =27527a(24) =52727a(25) =52757a(26) =57527a(27) =57557a(28) =57727a(29) =72227