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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 30 |
| 5 | 104 |
| 6 | 378 |
| 7 | 1414 |
| 8 | 5424 |
| 9 | 21208 |
| 10 | 84244 |
| 11 | 339008 |
| 12 | 1379173 |
| 13 | 5663078 |
| 14 | 23439651 |
| 15 | 97692524 |
| 16 | 409650348 |
| 17 | 1727034770 |
| 18 | 7315915371 |
| 19 | 31124324364 |
| 20 | 132926220818 |
| 21 | 569695276362 |
| 22 | 2449395461726 |
| 23 | 10561857055472 |
| 24 | 45664873651576 |
[1,1,3,9,30,104,378,1414,5424,21208,84244,339008, 1379173,5663078,23439651,97692524,409650348, 1727034770,7315915371,31124324364,132926220818, 569695276362,2449395461726,10561857055472, 45664873651576] |