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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 96 |
| 3 | 864 |
| 4 | 48384 |
| 5 | 1209600 |
| 6 | 5702400 |
| 7 | 25427001600 |
| 8 | 203416012800 |
| 9 | 31122649958400 |
| 10 | 53757304473600 |
| 11 | 71550972254361600 |
| 12 | 7446481275340800 |
| 13 | 278118629152703539200 |
| 14 | 278118629152703539200 |
| 15 | 40327201227142013184000 |
| 16 | 588302700254777604096000 |
[1,4,96,864,48384,1209600,5702400,25427001600, 203416012800,31122649958400,53757304473600, 71550972254361600,7446481275340800, 278118629152703539200,278118629152703539200, 40327201227142013184000,588302700254777604096000] |