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| n | a(n) |
|---|---|
| 1 | 21 |
| 2 | 103 |
| 3 | 125 |
| 4 | 368 |
| 5 | 1245 |
| 6 | 3910 |
| 7 | 11438 |
| 8 | 34687 |
| 9 | 106558 |
| 10 | 317866 |
| 11 | 952180 |
| 12 | 2866802 |
| 13 | 8566865 |
| 14 | 25602599 |
| 15 | 76565334 |
| 16 | 228533963 |
| 17 | 682228237 |
| 18 | 2036249074 |
| 19 | 6073671043 |
| 20 | 18119697325 |
| 21 | 54049396886 |
| 22 | 161180119634 |
| 23 | 480704637867 |
| 24 | 1433586580256 |
[21,103,125,368,1245,3910,11438,34687,106558, 317866,952180,2866802,8566865,25602599,76565334, 228533963,682228237,2036249074,6073671043, 18119697325,54049396886,161180119634,480704637867, 1433586580256] |