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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 16 |
| 3 | 504 |
| 4 | 28800 |
| 5 | 2620800 |
| 6 | 348364800 |
| 7 | 63707212800 |
| 8 | 15343379251200 |
| 9 | 4707627724800000 |
| 10 | 1792664637603840000 |
| 11 | 829619584788234240000 |
| 12 | 458592296933263933440000 |
| 13 | 298435681233688170332160000 |
| 14 | 225843218230899155927040000000 |
| 15 | 196652982274555440023470080000000 |
[1,1,16,504,28800,2620800,348364800,63707212800, 15343379251200,4707627724800000, 1792664637603840000,829619584788234240000, 458592296933263933440000, 298435681233688170332160000, 225843218230899155927040000000, 196652982274555440023470080000000] |