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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | -1 |
| 2 | 14 |
| 3 | -35 |
| 4 | 364 |
| 5 | -14560 |
| 6 | 79040 |
| 7 | -1521520 |
| 8 | 304304000 |
| 9 | -852051200 |
| 10 | 24012352000 |
| 11 | -2245154912000 |
| 12 | 25560225152000 |
| 13 | -949379791360000 |
| 14 | 114305326879744000 |
| 15 | -1643139073896320000 |
| 16 | 75777707878512640000 |
| 17 | -33493746882302586880000 |
| 18 | 193911166160699187200000 |
| 19 | -10684505255454525214720000 |
| 20 | 1862156630236360108851200000 |
[2,-1,14,-35,364,-14560,79040,-1521520,304304000, -852051200,24012352000,-2245154912000, 25560225152000,-949379791360000, 114305326879744000,-1643139073896320000, 75777707878512640000,-33493746882302586880000, 193911166160699187200000, -10684505255454525214720000, 1862156630236360108851200000] |