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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 14 |
| 6 | 41 |
| 7 | 124 |
| 8 | 384 |
| 9 | 1212 |
| 10 | 3885 |
| 11 | 12613 |
| 12 | 41389 |
| 13 | 137055 |
| 14 | 457403 |
| 15 | 1536935 |
| 16 | 5195215 |
| 17 | 17654059 |
| 18 | 60273846 |
| 19 | 206654787 |
| 20 | 711236960 |
| 21 | 2456296348 |
| 22 | 8509633845 |
| 23 | 29565682912 |
| 24 | 102993430854 |
| 25 | 359654460720 |
| 26 | 1258739058760 |
| 27 | 4414576865348 |
| 28 | 15512503485377 |
| 29 | 54608086597058 |
[1,1,2,5,14,41,124,384,1212,3885,12613,41389, 137055,457403,1536935,5195215,17654059,60273846, 206654787,711236960,2456296348,8509633845, 29565682912,102993430854,359654460720, 1258739058760,4414576865348,15512503485377, 54608086597058] |