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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1681 |
| 3 | 976 |
| 4 | 20277009 |
| 5 | 433687328 |
| 6 | 420771471561 |
| 7 | 29037336149952 |
| 8 | 10986555692499984 |
[0,1681,976,20277009,433687328,420771471561, 29037336149952,10986555692499984] |