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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -2 |
| 3 | 6 |
| 4 | -24 |
| 5 | 140 |
| 6 | -992 |
| 7 | 8456 |
| 8 | -84224 |
| 9 | 957840 |
| 10 | -12257792 |
| 11 | 174293856 |
| 12 | -2726068224 |
| 13 | 46514037440 |
| 14 | -859790139392 |
| 15 | 17115342333056 |
| 16 | -365041325441024 |
| 17 | 8304761365213440 |
| 18 | -200743379109281792 |
| 19 | 5137820023434733056 |
| 20 | -138802611894431514624 |
| 21 | 3947233200665413667840 |
| 22 | -117862929315296278740992 |
[0,1,-2,6,-24,140,-992,8456,-84224,957840, -12257792,174293856,-2726068224,46514037440, -859790139392,17115342333056,-365041325441024, 8304761365213440,-200743379109281792, 5137820023434733056,-138802611894431514624, 3947233200665413667840,-117862929315296278740992] |