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

Terms

a(0) =1a(1) =4a(2) =7a(3) =8a(4) =11a(5) =15a(6) =16a(7) =19a(8) =24a(9) =28a(10) =33a(11) =42a(12) =43a(13) =45a(14) =54a(15) =69a(16) =71a(17) =79a(18) =87a(19) =92a(20) =118a(21) =121a(22) =137a(23) =153a(24) =171a(25) =188a(26) =199a(27) =245a(28) =248a(29) =293