Numbers k such that (10^k - 13)/3 is prime.

Terms

a(0) =2a(1) =4a(2) =5a(3) =8a(4) =11a(5) =25a(6) =35a(7) =270a(8) =401a(9) =613a(10) =635a(11) =768a(12) =1283a(13) =2941a(14) =3409a(15) =4266a(16) =4391a(17) =10744a(18) =22979a(19) =26766a(20) =27743a(21) =35514a(22) =59174a(23) =86906a(24) =99239a(25) =154494