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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 64 |
| 3 | 716430 |
| 4 | 93604950539 |
| 5 | 314892411482182670 |
| 6 | 40799258353982022255077487 |
[1,64,716430,93604950539,314892411482182670, 40799258353982022255077487] |