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| n | a(n) |
|---|---|
| 1 | 11 |
| 2 | 13 |
| 3 | 17 |
| 4 | 19 |
| 5 | 199 |
| 6 | 1777 |
| 7 | 1999 |
| 8 | 199999 |
| 9 | 19999999 |
| 10 | 1777777777 |
| 11 | 17777777777777 |
| 12 | 1333333333333333 |
| 13 | 1111111111111111111 |
| 14 | 11111111111111111111111 |
| 15 | 199999999999999999999999999 |
| 16 | 1999999999999999999999999999 |
[11,13,17,19,199,1777,1999,199999,19999999, 1777777777,17777777777777,1333333333333333, 1111111111111111111,11111111111111111111111, 199999999999999999999999999, 1999999999999999999999999999] |