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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 8 |
| 4 | 48 |
| 5 | 259 |
| 6 | 1328 |
| 7 | 6622 |
| 8 | 32483 |
| 9 | 157739 |
| 10 | 761128 |
| 11 | 3657815 |
| 12 | 17534231 |
| 13 | 83925062 |
| 14 | 401363296 |
| 15 | 1918822635 |
| 16 | 9173429111 |
| 17 | 43866599736 |
| 18 | 209853869150 |
| 19 | 1004463716937 |
| 20 | 4810867131369 |
| 21 | 23057388013314 |
| 22 | 110588897473219 |
| 23 | 530808778620583 |
[1,8,48,259,1328,6622,32483,157739,761128,3657815, 17534231,83925062,401363296,1918822635,9173429111, 43866599736,209853869150,1004463716937, 4810867131369,23057388013314,110588897473219, 530808778620583] |