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 | 252 |
| 3 | 756756 |
| 4 | 457507512 |
| 5 | 184619047020 |
| 6 | 97087382008034 |
| 7 | 49254897805981056 |
| 8 | 22802419346927105088 |