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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 2 |
| 8 | 65 |
| 9 | 373 |
| 10 | 1472 |
| 11 | 4150 |
| 12 | 10977 |
| 13 | 23698 |
| 14 | 51195 |
| 15 | 95225 |
| 16 | 181674 |
| 17 | 304509 |
| 18 | 538484 |
| 19 | 834615 |
| 20 | 1381950 |
[0,0,0,0,0,0,2,65,373,1472,4150,10977,23698,51195, 95225,181674,304509,538484,834615,1381950] |