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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 22 |
| 5 | 93 |
| 6 | 790 |
| 7 | 7202 |
| 8 | 53884 |
| 9 | 640932 |
| 10 | 7175700 |
| 11 | 150597632 |
| 12 | 3323171712 |
| 13 | 92150022336 |
| 14 | 2899990063360 |
| 15 | 72285872321536 |
[1,2,3,22,93,790,7202,53884,640932,7175700, 150597632,3323171712,92150022336,2899990063360, 72285872321536] |