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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 2 |
| 5 | 3 |
| 6 | 14 |
| 7 | 30 |
| 8 | 143 |
| 9 | 728 |
| 10 | 3148 |
| 11 | 13566 |
| 12 | 56221 |
| 13 | 231308 |
| 14 | 939090 |
| 15 | 3793530 |
| 16 | 15237792 |
| 17 | 61020524 |
| 18 | 243678476 |
| 19 | 971345694 |
| 20 | 3866131073 |
| 21 | 15371516800 |
| 22 | 61064462784 |
| 23 | 242432019936 |
| 24 | 962016777729 |
| 25 | 3816117832536 |
| 26 | 15133756472226 |
[1,2,3,14,30,143,728,3148,13566,56221,231308, 939090,3793530,15237792,61020524,243678476, 971345694,3866131073,15371516800,61064462784, 242432019936,962016777729,3816117832536, 15133756472226] |