Numbers k such that (25*10^k - 331)/9 is prime.

Terms

a(0) =2a(1) =3a(2) =5a(3) =6a(4) =9a(5) =12a(6) =14a(7) =18a(8) =50a(9) =56a(10) =197a(11) =222a(12) =323a(13) =1256a(14) =1869a(15) =2690a(16) =4461a(17) =5828a(18) =46866a(19) =116601a(20) =141366