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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 187 |
| 6 | 7400 |
| 7 | 573865 |
| 8 | 58849205 |
| 9 | 8029423880 |
| 10 | 1380758051751 |
| 11 | 292145368826808 |
[1,0,1,4,187,7400,573865,58849205,8029423880, 1380758051751,292145368826808] |