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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 210 |
| 3 | 840 |
| 4 | 341880 |
| 5 | 71831760 |
| 6 | 64648584000 |
| 7 | 2216650756320 |
| 8 | 22861058133513600 |
[6,210,840,341880,71831760,64648584000, 2216650756320,22861058133513600] |