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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -1 |
| 3 | 5 |
| 4 | -60 |
| 5 | 1284 |
| 6 | -41520 |
| 7 | 1818480 |
| 8 | -99906240 |
| 9 | 6615483840 |
| 10 | -547250618880 |
| 11 | 64405640678400 |
| 12 | -10795621264243200 |
| 13 | 1874134190688883200 |
| 14 | -168421749610341427200 |
| 15 | -33755136201402065049600 |
| 16 | -12663782909587871373312000 |
| 17 | 33228107527756336198907904000 |
| 18 | -9780793395112024278861643776000 |
| 19 | -17994218650633803932152655560704000 |
| 20 | 15220589020710912054512237626933248000 |
| 21 | 19029826524235967059926689085261791232000 |
[1,-1,5,-60,1284,-41520,1818480,-99906240, 6615483840,-547250618880,64405640678400, -10795621264243200,1874134190688883200, -168421749610341427200,-33755136201402065049600, -12663782909587871373312000, 33228107527756336198907904000, -9780793395112024278861643776000, -17994218650633803932152655560704000, 15220589020710912054512237626933248000, 19029826524235967059926689085261791232000] |