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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | -3 |
| 4 | 16 |
| 5 | -50 |
| 6 | 560 |
| 7 | -4116 |
| 8 | 49376 |
| 9 | -495648 |
| 10 | 6885568 |
| 11 | -93060880 |
| 12 | 1541938880 |
| 13 | -25786609056 |
| 14 | 491456933760 |
| 15 | -9706007213280 |
| 16 | 211232587063296 |
| 17 | -4810337505293312 |
| 18 | 118025076480927744 |
| 19 | -3034967141004516864 |
| 20 | 82967370464849969152 |
| 21 | -2375277511119683573760 |
[0,0,2,-3,16,-50,560,-4116,49376,-495648,6885568, -93060880,1541938880,-25786609056,491456933760, -9706007213280,211232587063296,-4810337505293312, 118025076480927744,-3034967141004516864, 82967370464849969152,-2375277511119683573760] |