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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | 5 |
| 5 | 17 |
| 6 | 54 |
| 7 | 169 |
| 8 | 517 |
| 9 | 1559 |
| 10 | 4653 |
| 11 | 13787 |
| 12 | 40638 |
| 13 | 119333 |
| 14 | 349469 |
| 15 | 1021433 |
| 16 | 2981330 |
| 17 | 8693467 |
| 18 | 25333627 |
| 19 | 73795263 |
| 20 | 214915073 |
| 21 | 625855927 |
| 22 | 1822630172 |
| 23 | 5308552227 |
| 24 | 15464475465 |
| 25 | 45060652609 |
| 26 | 131334677147 |
| 27 | 382907083385 |
[1,1,5,17,54,169,517,1559,4653,13787,40638,119333, 349469,1021433,2981330,8693467,25333627,73795263, 214915073,625855927,1822630172,5308552227, 15464475465,45060652609,131334677147,382907083385] |