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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 63 |
| 4 | 3861 |
| 5 | 912060 |
| 6 | 823931109 |
| 7 | 2827364948343 |
| 8 | 36639801307739070 |
| 9 | 1783839514317792934491 |
[1,4,63,3861,912060,823931109,2827364948343, 36639801307739070,1783839514317792934491] |