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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | -24 |
| 3 | 300 |
| 4 | -2624 |
| 5 | 18126 |
| 6 | -105504 |
| 7 | 538296 |
| 8 | -2471424 |
| 9 | 10400997 |
| 10 | -40674128 |
| 11 | 149343012 |
| 12 | -519045888 |
| 13 | 1718732998 |
| 14 | -5451292992 |
| 15 | 16633756008 |
| 16 | -49010118656 |
| 17 | 139877936370 |
| 18 | -387749049720 |
| 19 | 1046413709980 |
| 20 | -2754808758144 |
| 21 | 7087483527072 |
[1,-24,300,-2624,18126,-105504,538296,-2471424, 10400997,-40674128,149343012,-519045888, 1718732998,-5451292992,16633756008,-49010118656, 139877936370,-387749049720,1046413709980, -2754808758144,7087483527072] |