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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -1 |
| 3 | 3 |
| 4 | -16 |
| 5 | 110 |
| 6 | -540 |
| 7 | -9240 |
| 8 | 292320 |
| 9 | 14908320 |
| 10 | -1639612800 |
| 11 | -33013854720 |
| 12 | 21046667685120 |
| 13 | -549927873855360 |
| 14 | -637881314775344640 |
| 15 | 76198391578224115200 |
| 16 | 41404329870413936025600 |
| 17 | -12499862617277304901632000 |
| 18 | -5212560012919105291193548800 |
| 19 | 3436632117109253032257698611200 |
| 20 | 1146156616720354265092896141312000 |
| 21 | -1615552168543480516126725021634560000 |
| 22 | -379914190499326491647463301427478528000 |
| 23 | 1268235921756889621556352102589895172096000 |
[1,-1,3,-16,110,-540,-9240,292320,14908320, -1639612800,-33013854720,21046667685120, -549927873855360,-637881314775344640, 76198391578224115200,41404329870413936025600, -12499862617277304901632000, -5212560012919105291193548800, 3436632117109253032257698611200, 1146156616720354265092896141312000, -1615552168543480516126725021634560000, -379914190499326491647463301427478528000, 1268235921756889621556352102589895172096000] |