Exactly 1 digit from {1,2,3,4,5,6,7,8,9} can precede a term to form a prime.

Terms

a(0) =89a(1) =107a(2) =139a(3) =141a(4) =169a(5) =189a(6) =223a(7) =249a(8) =267a(9) =313a(10) =379a(11) =383a(12) =403a(13) =453a(14) =497a(15) =587a(16) =589a(17) =633a(18) =667a(19) =751a(20) =757a(21) =763a(22) =799a(23) =859a(24) =893a(25) =899a(26) =913a(27) =959a(28) =961a(29) =977