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 | 5 |
| 1 | 23 |
| 2 | 95 |
| 3 | 383 |
| 4 | 1535 |
| 5 | 6143 |
| 6 | 24575 |
| 7 | 98303 |
| 8 | 393215 |
| 9 | 1572863 |
| 10 | 6291455 |
| 11 | 25165823 |
| 12 | 100663295 |
| 13 | 402653183 |
| 14 | 1610612735 |
| 15 | 6442450943 |
| 16 | 25769803775 |
| 17 | 103079215103 |
| 18 | 412316860415 |
| 19 | 1649267441663 |
| 20 | 6597069766655 |
| 21 | 26388279066623 |
| 22 | 105553116266495 |