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| n | a(n) |
|---|---|
| 2 | 2 |
| 3 | 6 |
| 4 | 68 |
| 5 | 876 |
| 6 | 43300 |
| 7 | 3026820 |
| 8 | 558858552 |
| 9 | 474109634808 |
| 10 | 1011861877473980 |
| 11 | 3520221010293816000 |
[2,6,68,876,43300,3026820,558858552,474109634808, 1011861877473980,3520221010293816000] |