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| n | a(n) |
|---|---|
| 1 | 9 |
| 2 | 99 |
| 3 | 9009 |
| 4 | 900900 |
| 5 | 90090000 |
| 6 | 9009000000 |
| 7 | 900900000000 |
| 8 | 90090000000000 |
| 9 | 9009000000000000 |
| 10 | 900900000000000000 |
| 11 | 90090000000000000000 |
| 12 | 9009000000000000000000 |
| 13 | 900900000000000000000000 |
[9,99,9009,900900,90090000,9009000000, 900900000000,90090000000000,9009000000000000, 900900000000000000,90090000000000000000, 9009000000000000000000,900900000000000000000000] |