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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 17 |
| 5 | 65 |
| 6 | 429 |
| 7 | 5631 |
| 8 | 146823 |
| 9 | 4351701 |
| 10 | 186793381 |
| 11 | 13761626501 |
| 12 | 1695235337657 |
[1,1,1,17,65,429,5631,146823,4351701,186793381, 13761626501,1695235337657] |