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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 5 |
| 4 | 13 |
| 5 | 45 |
| 6 | 205 |
| 7 | 1115 |
| 8 | 7305 |
| 9 | 54305 |
| 10 | 464425 |
| 11 | 4380675 |
| 12 | 46230925 |
| 13 | 528514025 |
| 14 | 6635260125 |
| 15 | 89124741875 |
| 16 | 1297262292625 |
| 17 | 20019445694625 |
| 18 | 331450831284625 |
| 19 | 5777919619047875 |
| 20 | 107221860383503125 |
| 21 | 2083573516715965625 |
[1,2,3,5,13,45,205,1115,7305,54305,464425,4380675, 46230925,528514025,6635260125,89124741875, 1297262292625,20019445694625,331450831284625, 5777919619047875,107221860383503125, 2083573516715965625] |