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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 4 |
| 3 | -6 |
| 4 | 27 |
| 5 | -150 |
| 6 | 900 |
| 7 | -5985 |
| 8 | 47565 |
| 9 | -442260 |
| 10 | 4450950 |
| 11 | -47868975 |
| 12 | 571153275 |
| 13 | -7552695150 |
| 14 | 106248542400 |
| 15 | -1572657211125 |
| 16 | 25057160753625 |
| 17 | -430628407209000 |
| 18 | 7779251376146250 |
| 19 | -146478623943526875 |
[1,0,4,-6,27,-150,900,-5985,47565,-442260,4450950, -47868975,571153275,-7552695150,106248542400, -1572657211125,25057160753625,-430628407209000, 7779251376146250,-146478623943526875] |