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 | 3 |
| 2 | 1 |
| 3 | 370 |
| 4 | 123456790 |
| 5 | 411522633744855967078189300 |
| 6 | 137174211248285322359396433470507544581618655692729766803840877914951989026063100 |