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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 0 |
| 5 | 1 |
| 6 | 0 |
| 7 | 7 |
| 8 | 0 |
| 9 | 39 |
| 10 | 0 |
| 11 | 419 |
| 12 | 0 |
| 13 | 7208 |
| 14 | 0 |
| 15 | 226512 |
| 16 | 0 |
| 17 | 7885970 |
| 18 | 0 |
| 19 | 345718580 |
| 20 | 0 |
| 21 | 18478915794 |
| 22 | 0 |
[1,0,1,0,7,0,39,0,419,0,7208,0,226512,0,7885970,0, 345718580,0,18478915794,0] |