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 | 4 |
| 3 | 216 |
| 4 | 643680 |
| 5 | 269568000000 |
| 6 | 39489843246336000000 |
| 7 | 2716675055795577271091911200000 |
| 8 | 130980129445039212210880200374052628780800000 |