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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 2 |
| 4 | 0 |
| 5 | -8 |
| 6 | -32 |
| 7 | 16 |
| 8 | 640 |
| 9 | 2304 |
| 10 | 1024 |
| 11 | -68352 |
| 12 | -661504 |
| 13 | -843776 |
| 14 | 25305088 |
| 15 | 221382656 |
| 16 | 948699136 |
| 17 | -9865887744 |
| 18 | -216606572544 |
| 19 | -888186732544 |
| 20 | 10006005547008 |
| 21 | 200433787207680 |
| 22 | 2013855760777216 |
| 23 | -8060855544971264 |
[0,1,2,2,0,-8,-32,16,640,2304,1024,-68352,-661504, -843776,25305088,221382656,948699136,-9865887744, -216606572544,-888186732544,10006005547008, 200433787207680,2013855760777216, -8060855544971264] |