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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 87 |
| 3 | 887 |
| 4 | 8887 |
| 5 | 88887 |
| 6 | 888887 |
| 7 | 8888887 |
| 8 | 88888887 |
| 9 | 888888887 |
| 10 | 8888888887 |
| 11 | 88888888887 |
| 12 | 888888888887 |
| 13 | 8888888888887 |
| 14 | 88888888888887 |
| 15 | 888888888888887 |
| 16 | 8888888888888887 |
| 17 | 88888888888888887 |
| 18 | 888888888888888887 |
| 19 | 8888888888888888887 |
| 20 | 88888888888888888887 |
| 21 | 888888888888888888887 |
[7,87,887,8887,88887,888887,8888887,88888887, 888888887,8888888887,88888888887,888888888887, 8888888888887,88888888888887,888888888888887, 8888888888888887,88888888888888887, 888888888888888887,8888888888888888887, 88888888888888888887,888888888888888888887] |