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| n | a(n) |
|---|---|
| 2 | 0 |
| 3 | 0 |
| 4 | 1 |
| 5 | 0 |
| 6 | 3 |
| 7 | 17 |
| 8 | 283 |
| 9 | 5069 |
| 10 | 132345 |
| 11 | 4451059 |
| 12 | 209875768 |
| 13 | 13364007134 |
[0,0,1,0,3,17,283,5069,132345,4451059,209875768, 13364007134] |