Primes having only {1, 5, 6} as digits.

Terms

a(0) =5a(1) =11a(2) =61a(3) =151a(4) =661a(5) =1151a(6) =1511a(7) =5651a(8) =6151a(9) =6551a(10) =6661a(11) =11161a(12) =11551a(13) =15161a(14) =15511a(15) =15551a(16) =15661a(17) =16111a(18) =16561a(19) =16651a(20) =16661a(21) =51151a(22) =51511a(23) =51551a(24) =55511a(25) =55661a(26) =56611a(27) =61151a(28) =61511a(29) =61561