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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 40319 |
| 9 | 362863 |
| 10 | 3628550 |
| 11 | 39913170 |
| 12 | 478947480 |
| 13 | 6226179960 |
| 14 | 87164597520 |
| 15 | 1307440134000 |
| 16 | 20918580896069 |
| 17 | 355608034188517 |
| 18 | 6400803479701178 |
| 19 | 121612584595293870 |
| 20 | 2432198062707745560 |
| 21 | 51075033128533094520 |
| 22 | 1123625953230764250960 |
[1,1,2,6,24,120,720,5040,40319,362863,3628550, 39913170,478947480,6226179960,87164597520, 1307440134000,20918580896069,355608034188517, 6400803479701178,121612584595293870, 2432198062707745560,51075033128533094520, 1123625953230764250960] |