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 | 5 |
| 2 | 17 |
| 3 | 41 |
| 4 | 193 |
| 5 | 257 |
| 6 | 12289 |
| 7 | 59393 |
| 8 | 65537 |
| 9 | 275201 |
| 10 | 786433 |
| 11 | 790529 |
| 12 | 8972801 |
| 13 | 13631489 |
| 14 | 21523361 |
| 15 | 134382593 |
| 16 | 155189249 |
| 17 | 448524289 |
| 18 | 524455937 |
| 19 | 847036417 |
| 20 | 3221225473 |
| 21 | 12348030977 |
| 22 | 22320686081 |
| 23 | 77309411329 |
| 24 | 206158430209 |
| 25 | 4638564679681 |
| 26 | 6597069766657 |
| 27 | 12079910333441 |