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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 45 |
| 6 | 151 |
| 7 | 523 |
| 8 | 1881 |
| 9 | 6965 |
| 10 | 26487 |
| 11 | 102601 |
| 12 | 404609 |
| 13 | 1619963 |
| 14 | 6568854 |
| 15 | 26939533 |
| 16 | 111602913 |
| 17 | 466477951 |
| 18 | 1965296691 |
| 19 | 8339774230 |
| 20 | 35620899135 |
| 21 | 153043448404 |
| 22 | 661093944092 |
| 23 | 2869845158073 |
| 24 | 12514815965529 |
| 25 | 54803343547278 |
| 26 | 240919643876389 |
| 27 | 1062914499955194 |
| 28 | 4705170248152238 |
[1,1,2,5,15,45,151,523,1881,6965,26487,102601, 404609,1619963,6568854,26939533,111602913, 466477951,1965296691,8339774230,35620899135, 153043448404,661093944092,2869845158073, 12514815965529,54803343547278,240919643876389, 1062914499955194,4705170248152238] |