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 | 4 |
| 3 | 22 |
| 4 | 103 |
| 5 | 508 |
| 6 | 2452 |
| 7 | 11929 |
| 8 | 57856 |
| 9 | 280930 |
| 10 | 1363495 |
| 11 | 6618856 |
| 12 | 32128024 |
| 13 | 155953777 |
| 14 | 757013548 |
| 15 | 3674624638 |
| 16 | 17836995847 |
| 17 | 86582609284 |
| 18 | 420280790476 |
| 19 | 2040085854985 |
| 20 | 9902784679240 |
| 21 | 48069126732586 |
| 22 | 233332442310919 |