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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 4 |
| 2 | 182 |
| 3 | 4744 |
| 4 | 287402 |
| 5 | 21494284 |
| 6 | 2264343902 |
| 7 | 304602955024 |
| 8 | 51600721945682 |
[2,4,182,4744,287402,21494284,2264343902, 304602955024,51600721945682] |