Indices of primes in sequence A006190.

Terms

a(0) =2a(1) =5a(2) =11a(3) =17a(4) =61a(5) =103a(6) =167a(7) =193a(8) =293a(9) =643a(10) =647a(11) =911a(12) =11243a(13) =29437a(14) =55021a(15) =80141