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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 20 |
| 3 | 1182 |
| 4 | 320314 |
| 5 | 471203608 |
| 6 | 3608789598890 |
| 7 | 144633234041629586 |
| 8 | 30422021680410630610470 |
| 9 | 33561342025910573963641656948 |
[2,20,1182,320314,471203608,3608789598890, 144633234041629586,30422021680410630610470, 33561342025910573963641656948] |