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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 74 |
| 3 | 63440 |
| 4 | 244728561176 |
| 5 | 13754897546985740953546112 |
| 6 | 181629101139670580935062344094172140654053010592464896 |
[4,74,63440,244728561176, 13754897546985740953546112, 18162910113967058093506234409417214065405301059246\ 4896] |