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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 42 |
| 4 | 984 |
| 5 | 48216 |
| 6 | 2869200 |
| 7 | 278125200 |
| 8 | 31015797120 |
| 9 | 4991834736000 |
| 10 | 896085889171200 |
| 11 | 215916261060729600 |
| 12 | 56895400548095155200 |
[1,2,42,984,48216,2869200,278125200,31015797120, 4991834736000,896085889171200,215916261060729600, 56895400548095155200] |