A044953 Numbers with no two equally numerous base 4 digits.

1, 2, 3, 5, 10, 15, 16, 17, 20, 21, 22, 23, 25, 26, 29, 31, 32, 34, 37, 38, 40, 41, 42, 43, 46, 47, 48, 51, 53, 55, 58, 59, 60, 61, 62, 63, 64, 69, 81, 84, 85, 86, 87, 89, 93, 101, 106, 117, 127, 128, 138, 149, 154, 162, 166, 168, 169, 170