A117668 Numbers a(n) such that if n is prime, a(n) is the n-th prime number and if n is not prime, a(n) is the n-th composite number.

1, 3, 5, 8, 11, 10, 17, 14, 15, 16, 31, 20, 41, 22, 24, 25, 59, 27, 67, 30, 32, 33, 83, 35, 36, 38, 39, 40, 109, 44, 127, 46, 48, 49, 50, 51, 157, 54, 55, 56, 479, 58, 191, 62, 63, 64, 211, 66, 68, 69, 70, 72, 241, 75, 76, 77, 78, 80, 277, 82, 283, 85, 86, 87, 88, 90, 331, 92