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 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 7 |
| 6 | 14 |
| 7 | 28 |
| 8 | 57 |
| 9 | 117 |
| 10 | 251 |
| 11 | 543 |
| 12 | 1209 |
| 13 | 2724 |
| 14 | 6251 |
| 15 | 14505 |
| 16 | 34055 |
| 17 | 80450 |
| 18 | 191166 |
| 19 | 455473 |
| 20 | 1086863 |
| 21 | 2592817 |