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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | -3 |
| 4 | 4 |
| 5 | -20 |
| 6 | -10 |
| 7 | 609 |
| 8 | -3880 |
| 9 | 32040 |
| 10 | -352742 |
| 11 | 3799565 |
| 12 | -44271460 |
| 13 | 571990068 |
| 14 | -7830460482 |
| 15 | 113493888585 |
| 16 | -1753811009808 |
| 17 | 28760379830416 |
| 18 | -498456016769742 |
| 19 | 9112758567973533 |
| 20 | -175322176912457996 |
[0,0,2,-3,4,-20,-10,609,-3880,32040,-352742, 3799565,-44271460,571990068,-7830460482, 113493888585,-1753811009808,28760379830416, -498456016769742,9112758567973533, -175322176912457996] |