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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 6 |
| 4 | 24 |
| 5 | 144 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 42096 |
| 9 | 399000 |
| 10 | 3753960 |
| 11 | 47500992 |
| 12 | 479001600 |
| 13 | 6230615736 |
| 14 | 87178291200 |
| 15 | 1457696910960 |
| 16 | 20929670124480 |
| 17 | 379536693283440 |
| 18 | 6510917252872320 |
| 19 | 121831439598033840 |
| 20 | 2432921507427445440 |
| 21 | 53921727651043042560 |
| 22 | 1134312679767378217920 |
[1,6,24,144,720,5040,42096,399000,3753960, 47500992,479001600,6230615736,87178291200, 1457696910960,20929670124480,379536693283440, 6510917252872320,121831439598033840, 2432921507427445440,53921727651043042560, 1134312679767378217920] |