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 | 1 |
| 1 | 0 |
| 2 | 480 |
| 3 | 161280 |
| 4 | 2229534720 |
| 5 | 45984153600000 |
| 6 | 3271798279766016000 |