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) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 11 |
| 4 | 23 |
| 5 | 95 |
| 6 | 191 |
| 7 | 383 |
| 8 | 1535 |
| 9 | 6143 |
| 10 | 24575 |
| 11 | 49151 |
| 12 | 196607 |
| 13 | 786431 |
| 14 | 3145727 |
| 15 | 12582911 |
| 16 | 50331647 |
| 17 | 201326591 |
| 18 | 805306367 |