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 | 3 |
| 3 | 9 |
| 4 | 30 |
| 5 | 102 |
| 6 | 352 |
| 7 | 1240 |
| 8 | 4443 |
| 9 | 16112 |
| 10 | 58900 |
| 11 | 216727 |
| 12 | 801880 |
| 13 | 2982327 |
| 14 | 11147622 |
| 15 | 41854916 |
| 16 | 157805863 |
| 17 | 597307573 |
| 18 | 2268487476 |
| 19 | 8639848112 |
| 20 | 32999949539 |
| 21 | 126498330700 |
| 22 | 485441076004 |
| 23 | 1865211479514 |
| 24 | 7176111235446 |
| 25 | 27644828367182 |
| 26 | 106633724636570 |