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 | 2 |
| 1 | 3 |
| 2 | 4 |
| 3 | 9 |
| 4 | 18 |
| 5 | 39 |
| 6 | 80 |
| 7 | 165 |
| 8 | 334 |
| 9 | 675 |
| 10 | 1356 |
| 11 | 2721 |
| 12 | 5450 |
| 13 | 10911 |
| 14 | 21832 |
| 15 | 43677 |
| 16 | 87366 |
| 17 | 174747 |
| 18 | 349508 |
| 19 | 699033 |
| 20 | 1398082 |
| 21 | 2796183 |
| 22 | 5592384 |
| 23 | 11184789 |
| 24 | 22369598 |
| 25 | 44739219 |
| 26 | 89478460 |
| 27 | 178956945 |
| 28 | 357913914 |
| 29 | 715827855 |
| 30 | 1431655736 |