Positions of primes among the powers of primes (A000961).

Terms

a(0) =2a(1) =3a(2) =5a(3) =6a(4) =9a(5) =10a(6) =12a(7) =13a(8) =14a(9) =17a(10) =18a(11) =20a(12) =21a(13) =22a(14) =23a(15) =25a(16) =26a(17) =27a(18) =29a(19) =30a(20) =31a(21) =32a(22) =34a(23) =35a(24) =36a(25) =37a(26) =38a(27) =39a(28) =40a(29) =41