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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 3 |
| 3 | 6 |
| 4 | 18 |
| 5 | 206 |
| 6 | 7888299 |
| 7 | 8112499583888855378066 |
| 8 | 42287533217833953489054778023401252726576585396037133766 |
[2,3,6,18,206,7888299,8112499583888855378066, 42287533217833953489054778023401252726576585396037\ 133766] |