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 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 698 |
| 7 | 4393 |
| 8 | 28551 |
| 9 | 187403 |
| 10 | 1231517 |
| 11 | 8080058 |
| 12 | 52905865 |
| 13 | 345820994 |