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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | -3 |
| 4 | 12 |
| 5 | -40 |
| 6 | 118 |
| 7 | 21 |
| 8 | -5208 |
| 9 | 88416 |
| 10 | -904518 |
| 11 | 8456085 |
| 12 | -36204300 |
| 13 | -582795720 |
| 14 | 25175931870 |
| 15 | -566080291035 |
| 16 | 10469521737360 |
| 17 | -151909726765440 |
| 18 | 1439879949016050 |
| 19 | 12663393759659565 |
| 20 | -1154176350734965860 |
[0,0,2,-3,12,-40,118,21,-5208,88416,-904518, 8456085,-36204300,-582795720,25175931870, -566080291035,10469521737360,-151909726765440, 1439879949016050,12663393759659565, -1154176350734965860] |