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| n | a(n) |
|---|---|
| 1 | 7 |
| 2 | 27 |
| 3 | 123 |
| 4 | 537 |
| 5 | 2343 |
| 6 | 10167 |
| 7 | 43959 |
| 8 | 189465 |
| 9 | 814359 |
| 10 | 3491691 |
| 11 | 14937987 |
| 12 | 63778065 |
| 13 | 271799175 |
| 14 | 1156345287 |
| 15 | 4911870063 |
| 16 | 20834207313 |
| 17 | 88251723687 |
| 18 | 373358554971 |
| 19 | 1577691954507 |
| 20 | 6659543294313 |
| 21 | 28081651307943 |
| 22 | 118299768626103 |
[7,27,123,537,2343,10167,43959,189465,814359, 3491691,14937987,63778065,271799175,1156345287, 4911870063,20834207313,88251723687,373358554971, 1577691954507,6659543294313,28081651307943, 118299768626103] |