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 | 103 |
| 5 | 127 |
| 6 | 337 |
| 7 | 1663 |
| 8 | 5407 |
| 9 | 8191 |
| 10 | 131071 |
| 11 | 346111 |
| 12 | 524287 |
| 13 | 2970343 |
| 14 | 3655807 |
| 15 | 22151167 |
| 16 | 109051903 |
| 17 | 617831551 |
| 18 | 1631461441 |
| 19 | 2007952543 |
| 20 | 2147483647 |
| 21 | 32127240703 |
| 22 | 194664464383 |
| 23 | 275716983697 |
| 24 | 958348132351 |
| 25 | 1357375919743 |
| 26 | 1670616516607 |
| 27 | 49834102882303 |
| 28 | 57349132609183 |