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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 42 |
| 6 | 210 |
| 7 | 1292 |
| 8 | 9352 |
| 9 | 77505 |
| 10 | 722294 |
| 11 | 7470003 |
| 12 | 84854788 |
| 13 | 1049924370 |
| 14 | 14052654158 |
| 15 | 202271440732 |
| 16 | 3115338658280 |
| 17 | 51118336314648 |
| 18 | 890201500701303 |
| 19 | 16397264064993185 |
| 20 | 318505677099378561 |
| 21 | 6506565509515408206 |
| 22 | 139449260758011488550 |
| 23 | 3128599281190613701180 |
[1,1,2,4,11,42,210,1292,9352,77505,722294,7470003, 84854788,1049924370,14052654158,202271440732, 3115338658280,51118336314648,890201500701303, 16397264064993185,318505677099378561, 6506565509515408206,139449260758011488550, 3128599281190613701180] |