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 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 5 |
| 6 | 13 |
| 7 | 42 |
| 8 | 155 |
| 9 | 636 |
| 10 | 2889 |
| 11 | 14321 |
| 12 | 76834 |
| 13 | 443157 |