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| n | a(n) |
|---|---|
| 5 | 42 |
| 6 | 1980 |
| 7 | 60060 |
| 8 | 1501500 |
| 9 | 33795762 |
| 10 | 714249900 |
| 11 | 14504269780 |
| 12 | 286931752800 |
| 13 | 5578065392900 |
| 14 | 107178276605400 |
| 15 | 2043352620527400 |
| 16 | 38758743724018500 |
| 17 | 732849800716048290 |
| 18 | 13831507110589591500 |
| 19 | 260829110106412824900 |
| 20 | 4917878997439418010000 |
| 21 | 92758042341429880435020 |
[42,1980,60060,1501500,33795762,714249900, 14504269780,286931752800,5578065392900, 107178276605400,2043352620527400, 38758743724018500,732849800716048290, 13831507110589591500,260829110106412824900, 4917878997439418010000,92758042341429880435020] |