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 | 2 |
| 2 | 5 |
| 3 | 21 |
| 4 | 102 |
| 5 | 639 |
| 6 | 4492 |
| 7 | 34032 |
| 8 | 272252 |
| 9 | 2267905 |
| 10 | 19502386 |
| 11 | 172111844 |
| 12 | 1551948268 |