| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 15 |
| 3 | 7 |
| 4 | 341 |
| 5 | 819 |
| 6 | 9709 |
| 7 | 2047 |
| 8 | 475107 |
| 9 | 31 |
| 10 | 3233097 |
| 11 | 5461 |
| 12 | 8388607 |
| 13 | 3556769739 |
| 14 | 31675383749 |
| 15 | 65498251203 |
| 16 | 575525617597 |
| 17 | 34359738367 |
| 18 | 549755813887 |
| 19 | 182518930210733 |
| 20 | 2047 |
| 21 | 37905296863701641 |
| 22 | 2251799813685247 |
[3,15,7,341,819,9709,2047,475107,31,3233097,5461, 8388607,3556769739,31675383749,65498251203, 575525617597,34359738367,549755813887, 182518930210733,2047,37905296863701641, 2251799813685247] |