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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 60 |
| 3 | 224 |
| 4 | 1736 |
| 5 | 6048 |
| 6 | 49920 |
| 7 | 136724 |
| 8 | 1107792 |
| 9 | 3718400 |
| 10 | 27060480 |
| 11 | 85449224 |
| 12 | 869499904 |
| 13 | 2136230474 |
| 14 | 15820920000 |
| 15 | 61359427584 |
| 16 | 461863805760 |
| 17 | 1338408456700 |
| 18 | 13177159680000 |
| 19 | 33558717136896 |
| 20 | 301282248701952 |
| 21 | 863701914880000 |
| 22 | 6313641012910080 |
| 23 | 20863951122979048 |
[7,60,224,1736,6048,49920,136724,1107792,3718400, 27060480,85449224,869499904,2136230474, 15820920000,61359427584,461863805760, 1338408456700,13177159680000,33558717136896, 301282248701952,863701914880000,6313641012910080, 20863951122979048] |