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 | 5 |
| 3 | 1700 |
| 4 | 601120000 |
| 5 | 3496121614336000000 |
| 6 | 5335507266769461885009920000000000 |
| 7 | 34161019296423817239835748940949012820787200000000000000 |