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 | 5 |
| 2 | -220 |
| 3 | -6345 |
| 4 | -64240 |
| 5 | -382849 |
| 6 | -1632960 |
| 7 | -5484865 |
| 8 | -15097600 |
| 9 | -32969025 |
| 10 | -39533824 |
| 11 | 148438175 |
| 12 | 1746800640 |
| 13 | 12244963295 |
| 14 | 76888375040 |
| 15 | 467622093951 |
| 16 | 2816814940160 |
| 17 | 16919683687295 |
| 18 | 101548936707840 |