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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 8 |
| 5 | 20 |
| 6 | 44 |
| 7 | 114 |
| 8 | 312 |
| 9 | 894 |
| 10 | 2639 |
| 11 | 8005 |
| 12 | 24362 |
| 13 | 74918 |
| 14 | 231123 |
| 15 | 722388 |
| 16 | 2276599 |
| 17 | 7242497 |
| 18 | 23144119 |
| 19 | 74203799 |
| 20 | 238684352 |