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 | 1 |
| 3 | 2 |
| 4 | 60 |
| 5 | 66360 |
| 6 | 4147236820 |
| 7 | 19902009929142960 |
| 8 | 10325801406739620796634430 |
| 9 | 776107138571279347069904891019268480 |
| 10 | 10911068841557131648034491574230872615312437194176 |