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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | -3 |
| 4 | 12 |
| 5 | -40 |
| 6 | -50 |
| 7 | 1449 |
| 8 | -23016 |
| 9 | 261288 |
| 10 | -2306342 |
| 11 | 15798365 |
| 12 | 33379940 |
| 13 | -3972201168 |
| 14 | 100308059878 |
| 15 | -1917671123655 |
| 16 | 28943854480688 |
| 17 | -288514829730256 |
| 18 | -1435208344849998 |
| 19 | 189049167829499229 |
[0,0,2,-3,12,-40,-50,1449,-23016,261288,-2306342, 15798365,33379940,-3972201168,100308059878, -1917671123655,28943854480688,-288514829730256, -1435208344849998,189049167829499229] |