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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2520 |
| 5 | 56586600 |
| 6 | 3718394156400 |
| 7 | 617944896216648000 |
| 8 | 231528006523766358806400 |
| 9 | 178355054529362612768336870400 |
| 10 | 262180318469859848392495320519360000 |
[0,0,1,2520,56586600,3718394156400, 617944896216648000,231528006523766358806400, 178355054529362612768336870400, 262180318469859848392495320519360000] |