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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 0 |
| 5 | 2 |
| 6 | 2 |
| 7 | 0 |
| 8 | 4 |
| 9 | 20 |
| 10 | 88 |
| 11 | 18 |
| 12 | 0 |
| 13 | 224 |
| 14 | 0 |
| 15 | 0 |
| 16 | 1234 |
| 17 | 60428 |
| 18 | 5742 |
| 19 | 0 |
| 20 | 9276 |
[1,1,1,0,2,2,0,4,20,88,18,0,224,0,0,1234,60428, 5742,0,9276] |