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 | 5 |
| 1 | 140 |
| 2 | 2744420 |
| 3 | 20670535451567121260 |
| 4 | 8831921094058107711185956797335984862612406515067837739780 |