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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 0 |
| 5 | -16 |
| 6 | 24 |
| 7 | 104 |
| 8 | -256 |
| 9 | -1600 |
| 10 | 5632 |
| 11 | 29952 |
| 12 | -156032 |
| 13 | -644736 |
| 14 | 4761600 |
| 15 | 18383616 |
| 16 | -178225152 |
| 17 | -645554176 |
| 18 | 8081772544 |
| 19 | 25645936640 |
| 20 | -422364381184 |
| 21 | -1160636121088 |
| 22 | 25184814366720 |
| 23 | 60217271582720 |
| 24 | -1713906141986816 |
[1,-1,0,2,0,-16,24,104,-256,-1600,5632,29952, -156032,-644736,4761600,18383616,-178225152, -645554176,8081772544,25645936640,-422364381184, -1160636121088,25184814366720,60217271582720, -1713906141986816] |