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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 17 |
| 5 | 49 |
| 6 | 329 |
| 7 | 4511 |
| 8 | 91215 |
| 9 | 2775809 |
| 10 | 118081991 |
| 11 | 8300875867 |
| 12 | 930028727469 |
| 13 | 155873672022641 |
[1,1,1,17,49,329,4511,91215,2775809,118081991, 8300875867,930028727469,155873672022641] |