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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | -3 |
| 4 | 14 |
| 5 | -15 |
| 6 | -136 |
| 7 | 1197 |
| 8 | -5776 |
| 9 | -255 |
| 10 | 420224 |
| 11 | -5448003 |
| 12 | 30166784 |
| 13 | 241437105 |
| 14 | -8354415616 |
| 15 | 104019879597 |
| 16 | -291139373056 |
| 17 | -17849464279935 |
| 18 | 456381834297344 |
| 19 | -5108933510880003 |
| 20 | -26967886768439296 |
| 21 | 2525823613297136625 |
[0,1,-1,-3,14,-15,-136,1197,-5776,-255,420224, -5448003,30166784,241437105,-8354415616, 104019879597,-291139373056,-17849464279935, 456381834297344,-5108933510880003, -26967886768439296,2525823613297136625] |