A028424 Clog sequence in base 3. Right to left concatenation of n,int(log_3(n)),int(log_3(int(log_3(n)))),... in base 3.

1, 2, 12, 13, 14, 15, 16, 17, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 999, 1000, 1001, 1002, 1003, 1004, 1005, 1006, 1007, 1008, 1009, 1010, 1011, 1012, 1013, 1014, 1015, 1016, 1017, 1018, 1019, 1020, 1021, 1022, 1023