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| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 13 |
| 2 | 47 |
| 3 | 161 |
| 4 | 567 |
| 5 | 1969 |
| 6 | 6887 |
| 7 | 24001 |
| 8 | 83799 |
| 9 | 292305 |
| 10 | 1020103 |
| 11 | 3559137 |
| 12 | 12419383 |
| 13 | 43333873 |
| 14 | 151206055 |
| 15 | 527598593 |
| 16 | 1840949015 |
| 17 | 6423592977 |
| 18 | 22413786247 |
| 19 | 78208138529 |
| 20 | 272890816759 |
| 21 | 952194714417 |
| 22 | 3322482302055 |
| 23 | 11593099229761 |
| 24 | 40451669182167 |
| 25 | 141147546049105 |
| 26 | 492504521037895 |
[4,13,47,161,567,1969,6887,24001,83799,292305, 1020103,3559137,12419383,43333873,151206055, 527598593,1840949015,6423592977,22413786247, 78208138529,272890816759,952194714417, 3322482302055,11593099229761,40451669182167, 141147546049105,492504521037895] |