A080903 a(1)=1; for n>1, a(n)=a(n-1)+4 if n is already in the sequence, a(n)=a(n-1)+2 otherwise.

1, 3, 7, 9, 11, 13, 17, 19, 23, 25, 29, 31, 35, 37, 39, 41, 45, 47, 51, 53, 55, 57, 61, 63, 67, 69, 71, 73, 77, 79, 83, 85, 87, 89, 93, 95, 99, 101, 105, 107, 111, 113, 115, 117, 121, 123, 127, 129, 131, 133, 137, 139, 143, 145, 149, 151, 155, 157, 159