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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 28 |
| 4 | 87 |
| 5 | 271 |
| 6 | 843 |
| 7 | 2619 |
| 8 | 8123 |
| 9 | 25153 |
| 10 | 77763 |
| 11 | 240054 |
| 12 | 740017 |
| 13 | 2278329 |
| 14 | 7006093 |
| 15 | 21520872 |
| 16 | 66039651 |
| 17 | 202462113 |
| 18 | 620164491 |
| 19 | 1898109900 |
| 20 | 5805127269 |
| 21 | 17741909157 |
| 22 | 54188530641 |
| 23 | 165405964227 |
| 24 | 504601360389 |
| 25 | 1538559689751 |
| 26 | 4688812503053 |
| 27 | 14282580916834 |
| 28 | 43486805133903 |
[1,3,9,28,87,271,843,2619,8123,25153,77763,240054, 740017,2278329,7006093,21520872,66039651, 202462113,620164491,1898109900,5805127269, 17741909157,54188530641,165405964227,504601360389, 1538559689751,4688812503053,14282580916834, 43486805133903] |