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| n | a(n) |
|---|---|
| 1 | 6 |
| 2 | 26 |
| 3 | 144 |
| 4 | 1272 |
| 5 | 15192 |
| 6 | 286392 |
| 7 | 7648032 |
| 8 | 314011868 |
| 9 | 18986004296 |
| 10 | 1725663296600 |
| 11 | 237096836118080 |
| 12 | 48071903199959400 |
| 13 | 15027587384189632928 |
| 14 | 6819730931931151055960 |
| 15 | 4852231403635188536789728 |
[6,26,144,1272,15192,286392,7648032,314011868, 18986004296,1725663296600,237096836118080, 48071903199959400,15027587384189632928, 6819730931931151055960,4852231403635188536789728] |