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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 19 |
| 6 | 47 |
| 7 | 134 |
| 8 | 357 |
| 9 | 1031 |
| 10 | 2912 |
| 11 | 8612 |
| 12 | 25007 |
| 13 | 75378 |
| 14 | 223884 |
| 15 | 683915 |
| 16 | 2067578 |
| 17 | 6376800 |
| 18 | 19503546 |
| 19 | 60749341 |
| 20 | 187592661 |
| 21 | 587938043 |
| 22 | 1831377952 |
| 23 | 5773159368 |
| 24 | 18092820941 |
| 25 | 57328904204 |
| 26 | 180657986051 |
| 27 | 574735018826 |
| 28 | 1820143698295 |
| 29 | 5810522774503 |
| 30 | 18473074695503 |
[1,1,3,7,19,47,134,357,1031,2912,8612,25007,75378, 223884,683915,2067578,6376800,19503546,60749341, 187592661,587938043,1831377952,5773159368, 18092820941,57328904204,180657986051,574735018826, 1820143698295,5810522774503,18473074695503] |