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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 50 |
| 6 | 191 |
| 7 | 789 |
| 8 | 3566 |
| 9 | 17306 |
| 10 | 89871 |
| 11 | 496250 |
| 12 | 2901931 |
| 13 | 17901455 |
| 14 | 116129282 |
| 15 | 789973067 |
| 16 | 5620945352 |
| 17 | 41739598787 |
| 18 | 322802306649 |
| 19 | 2595133213658 |
| 20 | 21650633864406 |
| 21 | 187146890460633 |
| 22 | 1673639663735620 |
| 23 | 15464023782414504 |
| 24 | 147441877065741283 |
[1,1,2,5,15,50,191,789,3566,17306,89871,496250, 2901931,17901455,116129282,789973067,5620945352, 41739598787,322802306649,2595133213658, 21650633864406,187146890460633,1673639663735620, 15464023782414504,147441877065741283] |