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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 139 |
| 5 | 16683 |
| 6 | 2876300 |
| 7 | 703845255 |
| 8 | 235994839738 |
| 9 | 105035943170557 |
[0,0,1,139,16683,2876300,703845255,235994839738, 105035943170557] |