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 | 3 |
| 2 | 3 |
| 3 | 7 |
| 4 | 19 |
| 5 | 31 |
| 6 | 59 |
| 7 | 135 |
| 8 | 259 |
| 9 | 495 |
| 10 | 1035 |
| 11 | 2071 |
| 12 | 4051 |
| 13 | 8191 |
| 14 | 16475 |
| 15 | 32679 |
| 16 | 65443 |
| 17 | 131343 |
| 18 | 262059 |
| 19 | 523831 |
| 20 | 1049203 |
| 21 | 2097439 |
| 22 | 4192763 |
| 23 | 8389575 |
| 24 | 16779331 |
| 25 | 33550383 |
| 26 | 67108683 |
| 27 | 134226007 |
| 28 | 268427539 |
| 29 | 536862271 |
| 30 | 1073766299 |
| 31 | 2147476455 |