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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 16 |
| 6 | 51 |
| 7 | 177 |
| 8 | 621 |
| 9 | 2246 |
| 10 | 8245 |
| 11 | 30783 |
| 12 | 116257 |
| 13 | 443945 |
| 14 | 1710255 |
| 15 | 6640939 |
| 16 | 25961690 |
| 17 | 102105115 |
| 18 | 403701135 |
| 19 | 1603721999 |
| 20 | 6397931901 |
| 21 | 25621989760 |
| 22 | 102965680728 |
| 23 | 415091909292 |
| 24 | 1678226164646 |
| 25 | 6803121058354 |
| 26 | 27645628327636 |
[1,1,2,5,16,51,177,621,2246,8245,30783,116257, 443945,1710255,6640939,25961690,102105115, 403701135,1603721999,6397931901,25621989760, 102965680728,415091909292,1678226164646, 6803121058354,27645628327636] |