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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 80 |
| 3 | 187200 |
| 4 | 50918400000 |
| 5 | 2675955409920000000 |
| 6 | 40702283662588674048000000000 |
| 7 | 250658664786823821917343252480000000000000 |
| 8 | 832906513114759565863066815448211678822400000000000000000 |
| 9 | 1919381816160714520414106848157314737202346840876384256000000000000000000000 |
[1,2,80,187200,50918400000,2675955409920000000, 40702283662588674048000000000, 250658664786823821917343252480000000000000, 83290651311475956586306681544821167882240000000000\ 0000000, 19193818161607145204141068481573147372023468408763\ 84256000000000000000000000] |