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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | -8 |
| 5 | 52 |
| 6 | -312 |
| 7 | 1920 |
| 8 | -11752 |
| 9 | 72040 |
| 10 | -441448 |
| 11 | 2705368 |
| 12 | -16579176 |
| 13 | 101601976 |
| 14 | -622645288 |
| 15 | 3815745720 |
| 16 | -23383962344 |
| 17 | 143303497848 |
| 18 | -878204132520 |
| 19 | 5381881888440 |
| 20 | -32981685665896 |
| 21 | 202121044650488 |
| 22 | -1238654600718888 |
| 23 | 7590823719249208 |
| 24 | -46518702391430632 |
[1,0,2,-8,52,-312,1920,-11752,72040,-441448, 2705368,-16579176,101601976,-622645288,3815745720, -23383962344,143303497848,-878204132520, 5381881888440,-32981685665896,202121044650488, -1238654600718888,7590823719249208, -46518702391430632] |