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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 25 |
| 6 | 69 |
| 7 | 197 |
| 8 | 583 |
| 9 | 1762 |
| 10 | 5441 |
| 11 | 17042 |
| 12 | 54072 |
| 13 | 173334 |
| 14 | 560659 |
| 15 | 1827306 |
| 16 | 5995570 |
| 17 | 19787135 |
| 18 | 65643226 |
| 19 | 218777532 |
| 20 | 732181107 |
| 21 | 2459576149 |
| 22 | 8290442750 |
| 23 | 28031056619 |
| 24 | 95045477945 |
| 25 | 323112137130 |
| 26 | 1101073839413 |
| 27 | 3760472582922 |
| 28 | 12869488098939 |
| 29 | 44127605854574 |
[0,1,2,4,10,25,69,197,583,1762,5441,17042,54072, 173334,560659,1827306,5995570,19787135,65643226, 218777532,732181107,2459576149,8290442750, 28031056619,95045477945,323112137130, 1101073839413,3760472582922,12869488098939, 44127605854574] |