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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 122 |
| 5 | 2194432 |
| 6 | 1860799032530519872 |
| 7 | 26520691877985842130274557505490676978655683245437940 |
[1,1,1,4,122,2194432,1860799032530519872, 26520691877985842130274557505490676978655683245437\ 940] |