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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 0 |
| 5 | 3 |
| 6 | -24 |
| 7 | 61 |
| 8 | -256 |
| 9 | 1383 |
| 10 | -5632 |
| 11 | 28345 |
| 12 | -156032 |
| 13 | 808299 |
| 14 | -4761600 |
| 15 | 28955317 |
| 16 | -178225152 |
| 17 | 1188919631 |
| 18 | -8081772544 |
| 19 | 56978370417 |
| 20 | -422364381184 |
| 21 | 3196912985683 |
| 22 | -25184814366720 |
| 23 | 205147130407981 |
| 24 | -1713906141986816 |
[1,-1,0,1,0,3,-24,61,-256,1383,-5632,28345, -156032,808299,-4761600,28955317,-178225152, 1188919631,-8081772544,56978370417,-422364381184, 3196912985683,-25184814366720,205147130407981, -1713906141986816] |