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 | 1 |
| 2 | -6 |
| 3 | -258 |
| 4 | 77400 |
| 5 | 162617400 |
| 6 | -2391451484400 |
| 7 | -246183190158589200 |
| 8 | 177399606828279377520000 |
| 9 | 894839274162813664365761520000 |
| 10 | -31596243236160097777438406008857120000 |
| 11 | -7809512095098558650122990001755435531352160000 |
| 12 | 13511712475016607822799577492128185918816231362544000000 |