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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 48 |
| 3 | 1280 |
| 4 | 69632 |
| 5 | 7602176 |
| 6 | 1660944384 |
| 7 | 725849473024 |
| 8 | 634418209226752 |
| 9 | 1109011408239984640 |
| 10 | 3877275019992826380288 |
| 11 | 27111105978154633171828736 |
| 12 | 379138479844261543254652092416 |
| 13 | 10604214183559196000870296488771584 |
[1,4,48,1280,69632,7602176,1660944384, 725849473024,634418209226752,1109011408239984640, 3877275019992826380288,27111105978154633171828736, 379138479844261543254652092416, 10604214183559196000870296488771584] |