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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 5 |
| 8 | 38 |
| 9 | 330 |
| 10 | 3435 |
| 11 | 41823 |
| 12 | 614757 |
| 13 | 10678281 |
| 14 | 218040550 |
| 15 | 5180904503 |
[0,0,0,0,0,1,5,38,330,3435,41823,614757,10678281, 218040550,5180904503] |