This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 7 |
| 3 | 31 |
| 4 | 127 |
| 5 | 1279 |
| 6 | 3583 |
| 7 | 5119 |
| 8 | 6143 |
| 9 | 8191 |
| 10 | 81919 |
| 11 | 131071 |
| 12 | 524287 |
| 13 | 14680063 |
| 14 | 109051903 |
| 15 | 654311423 |
| 16 | 738197503 |
| 17 | 2147483647 |
| 18 | 21474836479 |
| 19 | 51539607551 |
| 20 | 824633720831 |
| 21 | 13743895347199 |
| 22 | 26388279066623 |
| 23 | 246290604621823 |