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| n | a(n) |
|---|---|
| 4 | 2 |
| 5 | 0 |
| 6 | 31 |
| 7 | 210 |
| 8 | 36876 |
| 9 | 568284 |
| 10 | 46154300 |
| 11 | 2932212900 |
| 12 | 1044426597950 |
[2,0,31,210,36876,568284,46154300,2932212900, 1044426597950] |