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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 10 |
| 5 | 218 |
| 6 | 10078 |
| 7 | 896756 |
| 8 | 151676112 |
| 9 | 47754337568 |
| 10 | 28229412456056 |
| 11 | 31665593711174080 |
[0,1,0,1,10,218,10078,896756,151676112, 47754337568,28229412456056,31665593711174080] |