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 | 7 |
| 3 | 17 |
| 4 | 37 |
| 5 | 79 |
| 6 | 163 |
| 7 | 333 |
| 8 | 673 |
| 9 | 1355 |
| 10 | 2719 |
| 11 | 5449 |
| 12 | 10909 |
| 13 | 21831 |
| 14 | 43675 |
| 15 | 87365 |
| 16 | 174745 |
| 17 | 349507 |
| 18 | 699031 |
| 19 | 1398081 |
| 20 | 2796181 |
| 21 | 5592383 |
| 22 | 11184787 |
| 23 | 22369597 |
| 24 | 44739217 |
| 25 | 89478459 |
| 26 | 178956943 |
| 27 | 357913913 |
| 28 | 715827853 |
| 29 | 1431655735 |