A252481 - OEIS

A252481 as a simple table

n	a(n)
1	1
2	10
3	11
4	12
5	21
6	100
7	101
8	102
9	110
10	111
11	112
12	120
13	121
14	122
15	123
16	132
17	201
18	210
19	211
20	212
21	213
22	221
23	231
24	312
25	321
26	1000
27	1001
28	1002
29	1010
30	1011
31	1012
32	1020
33	1021
34	1022
35	1023
36	1032
37	1100
38	1101
39	1102
40	1110
41	1111
42	1112
43	1120
44	1121
45	1122
46	1123
47	1132
48	1200
49	1201
50	1202
51	1203
52	1210
53	1211
54	1212
55	1213
56	1220
57	1221
58	1222
59	1223

[1,10,11,12,21,100,101,102,110,111,112,120,121, 122,123,132,201,210,211,212,213,221,231,312,321, 1000,1001,1002,1010,1011,1012,1020,1021,1022,1023, 1032,1100,1101,1102,1110,1111,1112,1120,1121,1122, 1123,1132,1200,1201,1202,1203,1210,1211,1212,1213, 1220,1221,1222,1223]