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 | 2 |
| 1 | 6 |
| 2 | 210 |
| 3 | 9260790 |
| 4 | 794226015149981778210 |
| 5 | 500993769952171221242360491304282624082148055373236400176882790 |