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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 105 |
| 3 | 3780 |
| 4 | 231525 |
| 5 | 21517650 |
| 6 | 2810132325 |
| 7 | 487540053000 |
| 8 | 107478429683625 |
| 9 | 28959878236038750 |
| 10 | 9172717463134850625 |
| 11 | 3251808972997572487500 |
| 12 | 1181538736415476892578125 |
[1,6,105,3780,231525,21517650,2810132325, 487540053000,107478429683625,28959878236038750, 9172717463134850625,3251808972997572487500, 1181538736415476892578125] |