A080579 a(1)=1; for n>1, a(n)=a(n-1)+1 if n is already in the sequence, a(n)=a(n-1)+4 otherwise.

1, 5, 9, 13, 14, 18, 22, 26, 27, 31, 35, 39, 40, 41, 45, 49, 53, 54, 58, 62, 66, 67, 71, 75, 79, 80, 81, 85, 89, 93, 94, 98, 102, 106, 107, 111, 115, 119, 120, 121, 122, 126, 130, 134, 135, 139, 143, 147, 148, 152, 156, 160, 161, 162, 166, 170, 174, 175