A094510 Smallest number distinct from n, not occurring earlier and having in binary representation exactly as many ones as n.

2, 1, 5, 8, 3, 9, 11, 4, 6, 12, 7, 10, 14, 13, 23, 32, 18, 17, 21, 24, 19, 25, 15, 20, 22, 28, 29, 26, 27, 39, 47, 16, 34, 33, 37, 40, 35, 41, 30, 36, 38, 44, 45, 42, 43, 51, 31, 65, 50, 49, 46, 56, 54, 53, 59, 52, 58, 57, 55, 71, 62, 61, 95, 128, 48, 68, 69, 66, 67, 73, 60