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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -6 |
| 3 | 54 |
| 4 | -552 |
| 5 | 6840 |
| 6 | -97200 |
| 7 | 1577520 |
| 8 | -28667520 |
| 9 | 578067840 |
| 10 | -12798777600 |
| 11 | 308836281600 |
| 12 | -8065907942400 |
| 13 | 226719600307200 |
| 14 | -6824229456844800 |
| 15 | 219010610827008000 |
| 16 | -7465397891567616000 |
| 17 | 269363867734241280000 |
| 18 | -10256545055212904448000 |
[0,1,-6,54,-552,6840,-97200,1577520,-28667520, 578067840,-12798777600,308836281600, -8065907942400,226719600307200,-6824229456844800, 219010610827008000,-7465397891567616000, 269363867734241280000,-10256545055212904448000] |