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| n | a(n) |
|---|---|
| 1 | 15 |
| 2 | 27 |
| 3 | 63 |
| 4 | 123 |
| 5 | 279 |
| 6 | 567 |
| 7 | 1143 |
| 8 | 2307 |
| 9 | 4623 |
| 10 | 9447 |
| 11 | 18927 |
| 12 | 38283 |
| 13 | 77139 |
| 14 | 154839 |
| 15 | 309747 |
| 16 | 620463 |
| 17 | 1241823 |
| 18 | 2483847 |
| 19 | 4967739 |
| 20 | 9935607 |
| 21 | 19892547 |
| 22 | 39785199 |
[15,27,63,123,279,567,1143,2307,4623,9447,18927, 38283,77139,154839,309747,620463,1241823,2483847, 4967739,9935607,19892547,39785199] |