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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 24 |
| 4 | 436 |
| 5 | 10656 |
| 6 | 328112 |
| 7 | 12183456 |
| 8 | 529242224 |
| 9 | 26309617536 |
| 10 | 1472135847072 |
| 11 | 91526938123008 |
| 12 | 6258004268952064 |
| 13 | 466599240364076544 |
| 14 | 37672137946943244288 |
| 15 | 3274012281487011586560 |
| 16 | 304724394621209905647360 |
| 17 | 30239686358027369113804800 |
| 18 | 3187164738879981461171955200 |
| 19 | 355548230503664593634743375872 |
[1,0,2,24,436,10656,328112,12183456,529242224, 26309617536,1472135847072,91526938123008, 6258004268952064,466599240364076544, 37672137946943244288,3274012281487011586560, 304724394621209905647360, 30239686358027369113804800, 3187164738879981461171955200, 355548230503664593634743375872] |