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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 13 |
| 4 | 1904 |
| 5 | 3016365 |
| 6 | 50771120400 |
| 7 | 8993476465721657 |
| 8 | 16670531837245286776832 |
| 9 | 322175275214070402711647486361 |
| 10 | 64754609334534873770923002355900227840 |
[1,1,13,1904,3016365,50771120400,8993476465721657, 16670531837245286776832, 322175275214070402711647486361, 64754609334534873770923002355900227840] |