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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 30 |
| 4 | 756 |
| 5 | 75600 |
| 6 | 7392 |
| 7 | 54486432000 |
| 8 | 4358914560 |
| 9 | 1905468364800 |
| 10 | 7602818775552000 |
| 11 | 6690480522485760000 |
| 12 | 4616431560515174400000 |
| 13 | 226851446883715670016000000 |
| 14 | 127036810254880775208960000 |
| 15 | 2210440498434925488635904000000 |
| 16 | 646080179971122507107008512000000 |
[1,1,1,30,756,75600,7392,54486432000,4358914560, 1905468364800,7602818775552000, 6690480522485760000,4616431560515174400000, 226851446883715670016000000, 127036810254880775208960000, 2210440498434925488635904000000, 646080179971122507107008512000000] |