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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 17 |
| 5 | 71 |
| 6 | 301 |
| 7 | 1275 |
| 8 | 5257 |
| 9 | 21711 |
| 10 | 88997 |
| 11 | 363395 |
| 12 | 1480385 |
| 13 | 6014423 |
| 14 | 24393245 |
| 15 | 98781323 |
| 16 | 399502841 |
| 17 | 1614022751 |
| 18 | 6514800277 |
| 19 | 26275725843 |
| 20 | 105904696369 |
| 21 | 426598453863 |
| 22 | 1717507247885 |
| 23 | 6911604624923 |
| 24 | 27802402448233 |
| 25 | 111796372691439 |
| 26 | 449398016848261 |
[0,1,3,17,71,301,1275,5257,21711,88997,363395, 1480385,6014423,24393245,98781323,399502841, 1614022751,6514800277,26275725843,105904696369, 426598453863,1717507247885,6911604624923, 27802402448233,111796372691439,449398016848261] |