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 | 126 |
| 3 | 672 |
| 4 | -36288 |
| 5 | -413280 |
| 6 | 15087870 |
| 7 | 275661792 |
| 8 | -6846707322 |
| 9 | -186737716704 |
| 10 | 3093536396160 |
| 11 | 126405712075104 |
| 12 | -1274633447433024 |
| 13 | -84873293805379968 |
| 14 | 385697576191762044 |
| 15 | 56246329449791661600 |
| 16 | 31646424393253329408 |