a(n) is the position of square of n-th prime among the powers of primes (A000961).

Terms

a(0) =4a(1) =8a(2) =15a(3) =24a(4) =42a(5) =54a(6) =79a(7) =92a(8) =121a(9) =171a(10) =188a(11) =248a(12) =293a(13) =314a(14) =364a(15) =446a(16) =526a(17) =559a(18) =651a(19) =719a(20) =750a(21) =857a(22) =935a(23) =1050a(24) =1215a(25) =1305a(26) =1348a(27) =1436a(28) =1479a(29) =1581