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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | -12 |
| 5 | 60 |
| 6 | -450 |
| 7 | 2940 |
| 8 | -16688 |
| 9 | 58464 |
| 10 | 506520 |
| 11 | -18245040 |
| 12 | 332343528 |
| 13 | -5206192992 |
| 14 | 71271712512 |
| 15 | -855046876320 |
| 16 | 7211743218432 |
| 17 | 15834692767104 |
| 18 | -2957850381938112 |
| 19 | 99133043643679104 |
| 20 | -2542788978368967552 |
[1,0,0,0,-12,60,-450,2940,-16688,58464,506520, -18245040,332343528,-5206192992,71271712512, -855046876320,7211743218432,15834692767104, -2957850381938112,99133043643679104, -2542788978368967552] |