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 | 0 |
| 1 | 1 |
| 2 | 5 |
| 3 | 7 |
| 4 | 23 |
| 5 | 31 |
| 6 | 63 |
| 7 | 127 |
| 8 | 383 |
| 9 | 511 |
| 10 | 1023 |
| 11 | 2047 |
| 12 | 4095 |
| 13 | 8191 |