Primes having only {1, 6, 9} as digits.

Terms

a(0) =11a(1) =19a(2) =61a(3) =191a(4) =199a(5) =619a(6) =661a(7) =691a(8) =911a(9) =919a(10) =991a(11) =1619a(12) =1669a(13) =1699a(14) =1999a(15) =6199a(16) =6619a(17) =6661a(18) =6691a(19) =6911a(20) =6961a(21) =6991a(22) =9161a(23) =9199a(24) =9619a(25) =9661a(26) =11119a(27) =11161a(28) =11699a(29) =11969