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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | 24 |
| 4 | 288 |
| 5 | 4800 |
| 6 | 103680 |
| 7 | 2741760 |
| 8 | 85800960 |
| 9 | 3100446720 |
| 10 | 127037030400 |
| 11 | 5819550105600 |
| 12 | 294727768473600 |
| 13 | 16350861400473600 |
| 14 | 986127353590579200 |
| 15 | 64238655955009536000 |
| 16 | 4495021381191204864000 |
| 17 | 336249161369543245824000 |
[0,0,2,24,288,4800,103680,2741760,85800960, 3100446720,127037030400,5819550105600, 294727768473600,16350861400473600, 986127353590579200,64238655955009536000, 4495021381191204864000,336249161369543245824000] |