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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 18 |
| 3 | 84 |
| 4 | 858 |
| 5 | 31122 |
| 6 | 3383898 |
| 7 | 188841114 |
| 8 | 68588585868 |
| 9 | 440400004044 |
| 10 | 7722272777722272 |
[2,18,84,858,31122,3383898,188841114,68588585868, 440400004044,7722272777722272] |