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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 12 |
| 6 | 36 |
| 7 | 104 |
| 8 | 331 |
| 9 | 1062 |
| 10 | 3519 |
| 11 | 11809 |
| 12 | 40327 |
| 13 | 139066 |
| 14 | 484698 |
| 15 | 1702819 |
| 16 | 6026452 |
| 17 | 21460248 |
| 18 | 76846950 |
| 19 | 276524978 |
| 20 | 999423375 |
| 21 | 3626370269 |
| 22 | 13205135288 |
| 23 | 48241233346 |
| 24 | 176757275833 |
| 25 | 649399348322 |
| 26 | 2391817886703 |
[1,1,2,5,12,36,104,331,1062,3519,11809,40327, 139066,484698,1702819,6026452,21460248,76846950, 276524978,999423375,3626370269,13205135288, 48241233346,176757275833,649399348322, 2391817886703] |