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 | 1 |
| 2 | 3 |
| 3 | 21 |
| 4 | 861 |
| 5 | 1275141 |
| 6 | 2551762438701 |
| 7 | 9546380157472159016030421 |
| 8 | 126857284256055227389078067834858327568823447932861 |