A075065 a(1) = 1 and then alternately even and odd composite numbers matching the parity of the index.

1, 4, 9, 6, 15, 8, 21, 10, 25, 12, 27, 14, 33, 16, 35, 18, 39, 20, 45, 22, 49, 24, 51, 26, 55, 28, 57, 30, 63, 32, 65, 34, 69, 36, 75, 38, 77, 40, 81, 42, 85, 44, 87, 46, 91, 48, 93, 50, 95, 52, 99, 54