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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | -6 |
| 4 | 0 |
| 5 | 0 |
| 6 | 360 |
| 7 | -5040 |
| 8 | 0 |
| 9 | -60480 |
| 10 | 3628800 |
| 11 | -39916800 |
| 12 | 19958400 |
| 13 | -3113510400 |
| 14 | 130767436800 |
| 15 | -1318571654400 |
| 16 | 3487131648000 |
| 17 | -355687428096000 |
| 18 | 12813639597158400 |
| 19 | -126713646259200000 |
| 20 | 1013709170073600000 |
| 21 | -85161707377883136000 |
| 22 | 2819368492175499264000 |
[1,0,0,-6,0,0,360,-5040,0,-60480,3628800, -39916800,19958400,-3113510400,130767436800, -1318571654400,3487131648000,-355687428096000, 12813639597158400,-126713646259200000, 1013709170073600000,-85161707377883136000, 2819368492175499264000] |