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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 20 |
| 4 | 22 |
| 5 | 200 |
| 6 | 202 |
| 7 | 220 |
| 8 | 222 |
| 9 | 2000 |
| 10 | 2002 |
| 11 | 2020 |
| 12 | 2022 |
| 13 | 2200 |
| 14 | 2202 |
| 15 | 2220 |
| 16 | 2222 |
| 17 | 20000 |
| 18 | 20002 |
| 19 | 20020 |
| 20 | 20022 |
| 21 | 20200 |
| 22 | 20202 |
| 23 | 20220 |
| 24 | 20222 |
| 25 | 22000 |
| 26 | 22002 |
| 27 | 22020 |
| 28 | 22022 |
| 29 | 22200 |
| 30 | 22202 |
| 31 | 22220 |
| 32 | 22222 |
| 33 | 200000 |
| 34 | 200002 |
| 35 | 200020 |
| 36 | 200022 |
| 37 | 200200 |
| 38 | 200202 |
| 39 | 200220 |
| 40 | 200222 |
[0,2,20,22,200,202,220,222,2000,2002,2020,2022, 2200,2202,2220,2222,20000,20002,20020,20022,20200, 20202,20220,20222,22000,22002,22020,22022,22200, 22202,22220,22222,200000,200002,200020,200022, 200200,200202,200220,200222] |