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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 2 |
| 6 | 5 |
| 7 | 11 |
| 8 | 25 |
| 9 | 66 |
| 10 | 131 |
| 11 | 349 |
| 12 | 708 |
| 13 | 1911 |
| 14 | 3856 |
| 15 | 10604 |
| 16 | 21597 |
| 17 | 59961 |
| 18 | 123266 |
| 19 | 345060 |
| 20 | 715198 |
| 21 | 2015416 |
| 22 | 4206926 |
| 23 | 11919257 |
| 24 | 25032840 |
| 25 | 71246129 |
| 26 | 150413234 |
| 27 | 429750208 |
| 28 | 911379241 |
| 29 | 2612614298 |
| 30 | 5562367173 |
| 31 | 15991792731 |
| 32 | 34164355260 |
[0,0,0,0,2,5,11,25,66,131,349,708,1911,3856,10604, 21597,59961,123266,345060,715198,2015416,4206926, 11919257,25032840,71246129,150413234,429750208, 911379241,2612614298,5562367173,15991792731, 34164355260] |