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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 52 |
| 6 | 202 |
| 7 | 869 |
| 8 | 4075 |
| 9 | 20645 |
| 10 | 112124 |
| 11 | 648649 |
| 12 | 3976633 |
| 13 | 25719630 |
| 14 | 174839120 |
| 15 | 1245131903 |
| 16 | 9263053753 |
| 17 | 71806323461 |
| 18 | 578719497070 |
| 19 | 4839515883625 |
| 20 | 41916097982471 |
| 21 | 375401824277096 |
| 22 | 3471395994487422 |
| 23 | 33099042344383885 |
| 24 | 325005134436155395 |
[1,1,2,5,15,52,202,869,4075,20645,112124,648649, 3976633,25719630,174839120,1245131903,9263053753, 71806323461,578719497070,4839515883625, 41916097982471,375401824277096,3471395994487422, 33099042344383885,325005134436155395] |