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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 20 |
| 2 | -658 |
| 3 | -55480 |
| 4 | 978892 |
| 5 | 254369200 |
| 6 | -90954680 |
| 7 | -1616554775200 |
| 8 | -31657485143920 |
| 9 | 13049369914414400 |
| 10 | 562429971828694240 |
| 11 | -126813734257930467200 |
| 12 | -9081834697300952909120 |
| 13 | 1428390476192666153388800 |
| 14 | 153479363950530629379812480 |
| 15 | -18087732454355158476398656000 |
[1,20,-658,-55480,978892,254369200,-90954680, -1616554775200,-31657485143920,13049369914414400, 562429971828694240,-126813734257930467200, -9081834697300952909120,1428390476192666153388800, 153479363950530629379812480, -18087732454355158476398656000] |