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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 11 |
| 4 | 49 |
| 5 | 273 |
| 6 | 1859 |
| 7 | 14731 |
| 8 | 131073 |
| 9 | 1287041 |
| 10 | 13822051 |
| 11 | 161149227 |
| 12 | 2024636273 |
| 13 | 27227371345 |
| 14 | 389753084259 |
| 15 | 5912210812139 |
| 16 | 94679315407489 |
| 17 | 1595416629866625 |
| 18 | 28204870292970563 |
| 19 | 521740077282205387 |
| 20 | 10074781737635639601 |
[1,1,3,11,49,273,1859,14731,131073,1287041, 13822051,161149227,2024636273,27227371345, 389753084259,5912210812139,94679315407489, 1595416629866625,28204870292970563, 521740077282205387,10074781737635639601] |