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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 23 |
| 4 | 359 |
| 5 | 14055 |
| 6 | 1201128 |
| 7 | 242811875 |
| 8 | 111519014903 |
| 9 | 116476823660735 |
[1,2,23,359,14055,1201128,242811875,111519014903, 116476823660735] |