| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 32 |
| 3 | 264 |
| 4 | -9216 |
| 5 | -1548032 |
| 6 | -190744448 |
| 7 | -25395878400 |
| 8 | -3862395551744 |
| 9 | -674521189158912 |
| 10 | -133945803441307648 |
| 11 | -29717777068093669376 |
| 12 | -7172117320170458939392 |
| 13 | -1797012698406108143681536 |
[1,4,32,264,-9216,-1548032,-190744448, -25395878400,-3862395551744,-674521189158912, -133945803441307648,-29717777068093669376, -7172117320170458939392, -1797012698406108143681536] |