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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 27 |
| 2 | 127 |
| 3 | 399 |
| 4 | 1039 |
| 5 | 2439 |
| 6 | 5383 |
| 7 | 11439 |
| 8 | 23743 |
| 9 | 48567 |
| 10 | 98455 |
| 11 | 198495 |
| 12 | 398863 |
| 13 | 799911 |
| 14 | 1602343 |
| 15 | 3207567 |
| 16 | 6418399 |
| 17 | 12840471 |
| 18 | 25685047 |
| 19 | 51374655 |
| 20 | 102754351 |
| 21 | 205514247 |
| 22 | 411034567 |
| 23 | 822075759 |
| 24 | 1644158719 |
| 25 | 3288325239 |
| 26 | 6576658903 |
| 27 | 13153326879 |
| 28 | 26306663503 |
[1,27,127,399,1039,2439,5383,11439,23743,48567, 98455,198495,398863,799911,1602343,3207567, 6418399,12840471,25685047,51374655,102754351, 205514247,411034567,822075759,1644158719, 3288325239,6576658903,13153326879,26306663503] |