A043225 - OEIS

A043225 as a simple table

n	a(n)
1	12
2	21
3	112
4	120
5	210
6	221
7	312
8	321
9	412
10	421
11	512
12	521
13	612
14	621
15	712
16	721
17	812
18	821
19	912
20	921
21	1012
22	1021
23	1112
24	1120
25	1200
26	1312
27	1321
28	1412
29	1421
30	1512
31	1521
32	1612
33	1621
34	1712
35	1721
36	1812
37	1821
38	1912
39	1921
40	2012
41	2021

[12,21,112,120,210,221,312,321,412,421,512,521, 612,621,712,721,812,821,912,921,1012,1021,1112, 1120,1200,1312,1321,1412,1421,1512,1521,1612,1621, 1712,1721,1812,1821,1912,1921,2012,2021]