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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 37 |
| 5 | 111 |
| 6 | 333 |
| 7 | 333667 |
| 8 | 1001001 |
| 9 | 3003003 |
| 10 | 12345679 |
| 11 | 37037037 |
| 12 | 111111111 |
[1,3,9,37,111,333,333667,1001001,3003003,12345679, 37037037,111111111] |