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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 4 |
| 6 | 7 |
| 7 | 10 |
| 8 | 11 |
| 9 | 20 |
| 10 | 100 |
| 11 | 200 |
| 12 | 1000 |
| 13 | 2000 |
| 14 | 10000 |
| 15 | 20000 |
| 16 | 100000 |
| 17 | 200000 |
| 18 | 1000000 |
| 19 | 2000000 |
| 20 | 10000000 |
| 21 | 20000000 |
| 22 | 100000000 |
| 23 | 200000000 |
| 24 | 1000000000 |
| 25 | 2000000000 |
| 26 | 10000000000 |
| 27 | 20000000000 |
[0,1,2,3,4,7,10,11,20,100,200,1000,2000,10000, 20000,100000,200000,1000000,2000000,10000000, 20000000,100000000,200000000,1000000000, 2000000000,10000000000,20000000000] |