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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 144 |
| 4 | 17856 |
| 5 | 2156544 |
| 6 | 259117056 |
| 7 | 31102009344 |
| 8 | 3732432224256 |
| 9 | 447896453382144 |
| 10 | 53747684481171456 |
| 11 | 6449724779548114944 |
| 12 | 773967036949154758656 |
| 13 | 92876045955579714207744 |
[1,144,17856,2156544,259117056,31102009344, 3732432224256,447896453382144,53747684481171456, 6449724779548114944,773967036949154758656, 92876045955579714207744] |