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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 290 |
| 4 | 71320 |
| 5 | 22097600 |
| 6 | 8928102400 |
| 7 | 4644244774400 |
| 8 | 3046988353024000 |
| 9 | 2470747704449024000 |
| 10 | 2431736840968314880000 |
| 11 | 2859398101389251502080000 |
| 12 | 3962371103307529193881600000 |
| 13 | 6394280010754055221811609600000 |
[1,290,71320,22097600,8928102400,4644244774400, 3046988353024000,2470747704449024000, 2431736840968314880000,2859398101389251502080000, 3962371103307529193881600000, 6394280010754055221811609600000] |