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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 60 |
| 3 | 90 |
| 4 | 36720 |
| 5 | 12646368 |
| 6 | 22276800 |
| 7 | 126463680 |
| 8 | 4201148160 |
| 9 | 28770487200 |
| 10 | 287704872000 |
| 11 | 1446875426304 |
| 12 | 2548696550400 |
| 13 | 14468754263040 |
| 14 | 590325173932032 |
| 15 | 3291641594841600 |
| 16 | 8854877608980480 |
| 17 | 32916415948416000 |
[6,60,90,36720,12646368,22276800,126463680, 4201148160,28770487200,287704872000,1446875426304, 2548696550400,14468754263040,590325173932032, 3291641594841600,8854877608980480, 32916415948416000] |