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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 8 |
| 5 | 22 |
| 6 | 51 |
| 7 | 342 |
| 8 | 2609 |
| 9 | 16896 |
| 10 | 99114 |
| 11 | 876579 |
| 12 | 8551800 |
| 13 | 79595269 |
| 14 | 764804085 |
| 15 | 8905825760 |
[1,1,0,1,8,22,51,342,2609,16896,99114,876579, 8551800,79595269,764804085,8905825760] |