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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 9 |
| 5 | 31 |
| 6 | 205 |
| 7 | 1307 |
| 8 | 12227 |
| 9 | 171281 |
| 10 | 3266929 |
| 11 | 85166971 |
| 12 | 3120438693 |
| 13 | 149314103237 |
| 14 | 10059913232521 |
| 15 | 894685834014771 |
[1,1,1,9,31,205,1307,12227,171281,3266929, 85166971,3120438693,149314103237,10059913232521, 894685834014771] |