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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 624 |
| 7 | 4560 |
| 8 | 37440 |
| 9 | 323520 |
| 10 | 3167616 |
| 11 | 34387248 |
| 12 | 397398720 |
| 13 | 5179836888 |
| 14 | 69488212320 |
| 15 | 1032953884956 |
[1,2,6,24,120,624,4560,37440,323520,3167616, 34387248,397398720,5179836888,69488212320, 1032953884956] |