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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 32 |
| 2 | 408 |
| 3 | 3600 |
| 4 | 26040 |
| 5 | 166368 |
| 6 | 976640 |
| 7 | 5392704 |
| 8 | 28432288 |
| 9 | 144605184 |
| 10 | 714611200 |
| 11 | 3449705600 |
| 12 | 16333065216 |
| 13 | 76081271168 |
| 14 | 349524164224 |
| 15 | 1586790140800 |
| 16 | 7130144209024 |
| 17 | 31752978219904 |
| 18 | 140298397039232 |
| 19 | 615604372260736 |
[1,32,408,3600,26040,166368,976640,5392704, 28432288,144605184,714611200,3449705600, 16333065216,76081271168,349524164224, 1586790140800,7130144209024,31752978219904, 140298397039232,615604372260736] |