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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 6 |
| 5 | 29 |
| 6 | 124 |
| 7 | 499 |
| 8 | 1933 |
| 9 | 7307 |
| 10 | 27166 |
| 11 | 99841 |
| 12 | 363980 |
| 13 | 1319404 |
| 14 | 4763927 |
| 15 | 17155264 |
| 16 | 61672791 |
| 17 | 221499015 |
| 18 | 795198010 |
| 19 | 2854898575 |
| 20 | 10253237150 |
| 21 | 36846414395 |
| 22 | 132518215788 |
| 23 | 477049025009 |
| 24 | 1719101735260 |
| 25 | 6201858101192 |
| 26 | 22399768386170 |
| 27 | 80998670324341 |
| 28 | 293244129636085 |
[1,6,29,124,499,1933,7307,27166,99841,363980, 1319404,4763927,17155264,61672791,221499015, 795198010,2854898575,10253237150,36846414395, 132518215788,477049025009,1719101735260, 6201858101192,22399768386170,80998670324341, 293244129636085] |