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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 17 |
| 5 | 57 |
| 6 | 317 |
| 7 | 3151 |
| 8 | 61021 |
| 9 | 1767277 |
| 10 | 57009275 |
| 11 | 2869106215 |
| 12 | 240681795661 |
[1,1,1,17,57,317,3151,61021,1767277,57009275, 2869106215,240681795661] |