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 | 4 |
| 2 | 1120 |
| 3 | 79833600 |
| 4 | 3173289799680000 |
| 5 | 123650071173117090201600000 |
| 6 | 7337799401269093351612002462597120000000 |
| 7 | 951792703318385182295191545713146608287219712000000000000 |