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 | 3 |
| 3 | 5 |
| 4 | 9 |
| 5 | 15 |
| 6 | 27 |
| 7 | 49 |
| 8 | 93 |
| 9 | 179 |
| 10 | 351 |
| 11 | 693 |
| 12 | 1377 |
| 13 | 2743 |
| 14 | 5475 |
| 15 | 10937 |
| 16 | 21861 |
| 17 | 43707 |
| 18 | 87399 |
| 19 | 174781 |
| 20 | 349545 |
| 21 | 699071 |
| 22 | 1398123 |
| 23 | 2796225 |
| 24 | 5592429 |
| 25 | 11184835 |
| 26 | 22369647 |
| 27 | 44739269 |
| 28 | 89478513 |
| 29 | 178956999 |
| 30 | 357913971 |
| 31 | 715827913 |