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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 0 |
| 4 | 6 |
| 5 | 5 |
| 6 | 20 |
| 7 | 42 |
| 8 | 70 |
| 9 | 261 |
| 10 | 297 |
| 11 | 1430 |
| 12 | 1584 |
| 13 | 7293 |
| 14 | 9634 |
| 15 | 35945 |
| 16 | 60150 |
| 17 | 176596 |
| 18 | 366401 |
| 19 | 886977 |
| 20 | 2150421 |
| 21 | 4624410 |
| 22 | 12205074 |
| 23 | 25065216 |
| 24 | 67616872 |
| 25 | 139894305 |
| 26 | 369551925 |
| 27 | 793214982 |
| 28 | 2011977414 |
| 29 | 4517758504 |
| 30 | 10992821055 |
| 31 | 25669627965 |
| 32 | 60531471286 |
| 33 | 145112506352 |
[1,0,2,0,6,5,20,42,70,261,297,1430,1584,7293,9634, 35945,60150,176596,366401,886977,2150421,4624410, 12205074,25065216,67616872,139894305,369551925, 793214982,2011977414,4517758504,10992821055, 25669627965,60531471286,145112506352] |