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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | -1 |
| 3 | -3 |
| 4 | -3 |
| 5 | 20 |
| 6 | 150 |
| 7 | 504 |
| 8 | -343 |
| 9 | -18180 |
| 10 | -140220 |
| 11 | -500500 |
| 12 | 2032899 |
| 13 | 50210082 |
| 14 | 441768236 |
| 15 | 1740141480 |
| 16 | -13025325615 |
| 17 | -330558552376 |
| 18 | -3452606080848 |
| 19 | -16648495695792 |
| 20 | 136964192085395 |
| 21 | 4315989335784630 |
| 22 | 55121200672923924 |
| 23 | 352945156766431592 |
[1,0,-1,-3,-3,20,150,504,-343,-18180,-140220, -500500,2032899,50210082,441768236,1740141480, -13025325615,-330558552376,-3452606080848, -16648495695792,136964192085395,4315989335784630, 55121200672923924,352945156766431592] |