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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | -6 |
| 5 | 20 |
| 6 | 0 |
| 7 | -126 |
| 8 | 1260 |
| 9 | -4320 |
| 10 | 5040 |
| 11 | 180180 |
| 12 | -2601720 |
| 13 | 31309200 |
| 14 | -372756384 |
| 15 | 4877195400 |
| 16 | -70178799600 |
| 17 | 1099333347840 |
| 18 | -18429818232960 |
| 19 | 327676010785200 |
| 20 | -6146676161388000 |
| 21 | 121301442091851840 |
| 22 | -2512746856371628800 |
| 23 | 54527094987619716000 |
[1,0,0,3,-6,20,0,-126,1260,-4320,5040,180180, -2601720,31309200,-372756384,4877195400, -70178799600,1099333347840,-18429818232960, 327676010785200,-6146676161388000, 121301442091851840,-2512746856371628800, 54527094987619716000] |