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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 4 |
| 6 | 24 |
| 7 | 504 |
| 8 | 66012 |
| 9 | 181997601 |
| 10 | 65720971788709 |
| 11 | 65431225571591367370292 |
| 12 | 23523635785731871586396890786299881280 |
| 13 | 8419860898569880503664421048610377961601349941695806840602396 |
[0,0,0,1,1,4,24,504,66012,181997601, 65720971788709,65431225571591367370292, 23523635785731871586396890786299881280, 84198608985698805036644210486103779616013499416958\ 06840602396] |