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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 25 |
| 5 | 9380 |
| 6 | 3352561 |
| 7 | 20919129784 |
| 8 | 67388304885444 |
| 9 | 9468733259465993344 |
| 10 | 698854408853012410709764 |
[1,1,1,25,9380,3352561,20919129784,67388304885444, 9468733259465993344,698854408853012410709764] |