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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 12 |
| 4 | 48 |
| 5 | 144 |
| 6 | 1440 |
| 7 | 34560 |
| 8 | 483840 |
| 9 | 7257600 |
| 10 | 58060800 |
| 11 | 3135283200 |
| 12 | 125411328000 |
| 13 | 2633637888000 |
| 14 | 57940033536000 |
| 15 | 5562243219456000 |
| 16 | 27811216097280000 |
| 17 | 723091618529280000 |
| 18 | 6507824566763520000 |
| 19 | 364438175738757120000 |
| 20 | 327994358164881408000000 |
[1,2,12,48,144,1440,34560,483840,7257600,58060800, 3135283200,125411328000,2633637888000, 57940033536000,5562243219456000,27811216097280000, 723091618529280000,6507824566763520000, 364438175738757120000,327994358164881408000000] |