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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 8 |
| 3 | 48 |
| 4 | 384 |
| 5 | 1440 |
| 6 | 8640 |
| 7 | 40320 |
| 8 | 184320 |
| 9 | 829440 |
| 10 | 5529600 |
| 11 | 18247680 |
| 12 | 87588864 |
| 13 | 474439680 |
| 14 | 1532805120 |
| 15 | 7664025600 |
| 16 | 32699842560 |
| 17 | 130288435200 |
| 18 | 517321728000 |
| 19 | 2184247296000 |
| 20 | 9196830720000 |
| 21 | 38626689024000 |
| 22 | 188841590784000 |
[0,1,8,48,384,1440,8640,40320,184320,829440, 5529600,18247680,87588864,474439680,1532805120, 7664025600,32699842560,130288435200,517321728000, 2184247296000,9196830720000,38626689024000, 188841590784000] |