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 | 48 |
| 4 | 1935360 |
| 5 | 40493130637639680000 |
| 6 | 10654991354747516157752604498631700563938508800000000000 |