A086170 a(1)=1; a(n)=a(n-1)+1 if n is in the sequence; a(n)=a(n-1)+2 if n and (n-1) are not in the sequence; a(n)=a(n-1)+3 if n is not in the sequence but (n-1) is in the sequence.

1, 4, 6, 7, 10, 11, 12, 15, 17, 18, 19, 20, 23, 25, 26, 29, 30, 31, 32, 33, 36, 38, 39, 42, 43, 44, 47, 49, 50, 51, 52, 53, 54, 57, 59, 60, 63, 64, 65, 68, 70, 71, 72, 73, 76, 78, 79, 82, 83, 84, 85, 86, 87, 88, 91, 93, 94, 97, 98, 99, 102, 104, 105, 106, 107, 110, 112, 113