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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 7 |
| 6 | 31 |
| 7 | 331 |
| 8 | 12795 |
| 9 | 4642051 |
| 10 | 60935796571 |
| 11 | 283646808320375611 |
| 12 | 17285560913056915909539455163 |
| 13 | 4902995236325455290013100337511909917402705547 |
[1,1,1,3,7,31,331,12795,4642051,60935796571, 283646808320375611,17285560913056915909539455163, 4902995236325455290013100337511909917402705547] |