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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 32 |
| 4 | 531 |
| 5 | 20400 |
| 6 | 1707676 |
| 7 | 313358793 |
| 8 | 126050637852 |
| 9 | 111079912880127 |
| 10 | 214001518780274766 |
[1,4,32,531,20400,1707676,313358793,126050637852, 111079912880127,214001518780274766] |