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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 84 |
| 3 | 1680 |
| 4 | 66276 |
| 5 | 2731680 |
| 6 | 128704800 |
| 7 | 6555265920 |
| 8 | 355588928100 |
| 9 | 20247799145280 |
| 10 | 1198746727590384 |
| 11 | 73266532153214400 |
| 12 | 4598338364703822816 |
| 13 | 295145004688715301120 |
| 14 | 19311431876483926443264 |
[1,0,84,1680,66276,2731680,128704800,6555265920, 355588928100,20247799145280,1198746727590384, 73266532153214400,4598338364703822816, 295145004688715301120,19311431876483926443264] |