A073920 a(1)=1 and then odd numbers rearranged such that a(n) is prime if n is composite else vice-versa.

1, 9, 15, 3, 21, 5, 25, 7, 11, 13, 27, 17, 33, 19, 23, 29, 35, 31, 39, 37, 41, 43, 45, 47, 53, 59, 61, 67, 49, 71, 51, 73, 79, 83, 89, 97, 55, 101, 103, 107, 57, 109, 63, 113, 127, 131, 65, 137, 139, 149, 151, 157, 69, 163, 167, 173, 179, 181, 75, 191, 77, 193, 197, 199