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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 24 |
| 4 | 864 |
| 5 | 30592 |
| 6 | 1553920 |
| 7 | 117742464 |
| 8 | 11397335040 |
| 9 | 1412290109440 |
| 10 | 217673365676032 |
| 11 | 40748299759681536 |
| 12 | 9116312439290462208 |
| 13 | 2401574168877397737472 |
| 14 | 735827858439672282087424 |
[0,1,4,24,864,30592,1553920,117742464,11397335040, 1412290109440,217673365676032,40748299759681536, 9116312439290462208,2401574168877397737472, 735827858439672282087424] |