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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 1462 |
| 4 | 1584088 |
| 5 | 8616332520 |
| 6 | 71643177829872 |
| 7 | 1642669067898696816 |
[1,6,1462,1584088,8616332520,71643177829872, 1642669067898696816] |