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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 6 |
| 3 | 30 |
| 4 | 630 |
| 5 | 34650 |
| 6 | 47297250 |
| 7 | 309560501250 |
| 8 | 618190773193743750 |
| 9 | 66537433850544954015468750 |
| 10 | 65572844234095125006030612749369531250 |
| 11 | 70740128442809835497514843888197127919441136894531250 |
[2,6,30,630,34650,47297250,309560501250, 618190773193743750,66537433850544954015468750, 65572844234095125006030612749369531250, 70740128442809835497514843888197127919441136894531\ 250] |