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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 21 |
| 4 | 84 |
| 5 | 341 |
| 6 | 1445 |
| 7 | 6309 |
| 8 | 27788 |
| 9 | 125044 |
| 10 | 570195 |
| 11 | 2614993 |
| 12 | 12120861 |
| 13 | 56615783 |
| 14 | 265431493 |
| 15 | 1252372891 |
| 16 | 5937958979 |
| 17 | 28227542252 |
| 18 | 134746021085 |
| 19 | 645350756373 |
| 20 | 3096830635056 |
| 21 | 14903561941625 |
| 22 | 71893392943530 |
| 23 | 347324211311272 |
| 24 | 1681464054920885 |
| 25 | 8154591774594199 |
| 26 | 39593850266494760 |
| 27 | 192545631945019300 |
[1,2,6,21,84,341,1445,6309,27788,125044,570195, 2614993,12120861,56615783,265431493,1252372891, 5937958979,28227542252,134746021085,645350756373, 3096830635056,14903561941625,71893392943530, 347324211311272,1681464054920885,8154591774594199, 39593850266494760,192545631945019300] |