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| n | a(n) |
|---|---|
| 1 | 120 |
| 2 | 672 |
| 3 | 30240 |
| 4 | 32760 |
| 5 | 523776 |
| 6 | 2178540 |
| 7 | 23569920 |
| 8 | 45532800 |
| 9 | 142990848 |
| 10 | 459818240 |
| 11 | 1379454720 |
| 12 | 1476304896 |
| 13 | 14182439040 |
| 14 | 31998395520 |
| 15 | 43861478400 |
| 16 | 51001180160 |
| 17 | 66433720320 |
| 18 | 153003540480 |
| 19 | 403031236608 |
| 20 | 518666803200 |
[120,672,30240,32760,523776,2178540,23569920, 45532800,142990848,459818240,1379454720, 1476304896,14182439040,31998395520,43861478400, 51001180160,66433720320,153003540480,403031236608, 518666803200] |