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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 17 |
| 5 | 49 |
| 6 | 237 |
| 7 | 3143 |
| 8 | 61525 |
| 9 | 1581763 |
| 10 | 52804881 |
| 11 | 3069718147 |
| 12 | 283686428107 |
| 13 | 37198650400311 |
[1,1,1,17,49,237,3143,61525,1581763,52804881, 3069718147,283686428107,37198650400311] |