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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 24 |
| 3 | 8 |
| 4 | 2880 |
| 5 | 288 |
| 6 | 362880 |
| 7 | 17280 |
| 8 | 29030400 |
| 9 | 89600 |
| 10 | 958003200 |
| 11 | 17418240 |
| 12 | 31384184832000 |
| 13 | 402361344000 |
| 14 | 62768369664000 |
| 15 | 295206912 |
| 16 | 512189896458240000 |
| 17 | 342372925440000 |
| 18 | 919636959090769920000 |
| 19 | 5377993912811520000 |
| 20 | 674400436666564608000000 |
| 21 | 89903156428800000 |
[2,24,8,2880,288,362880,17280,29030400,89600, 958003200,17418240,31384184832000,402361344000, 62768369664000,295206912,512189896458240000, 342372925440000,919636959090769920000, 5377993912811520000,674400436666564608000000, 89903156428800000] |