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 | 0 |
| 1 | -4 |
| 2 | 60 |
| 3 | -1096 |
| 4 | 19640 |
| 5 | -352460 |
| 6 | 6324596 |
| 7 | -113490320 |
| 8 | 2036501104 |
| 9 | -36543529620 |
| 10 | 655747031980 |
| 11 | -11766903046104 |
| 12 | 211148507797800 |
| 13 | -3788906237314396 |
| 14 | 67989163763861220 |
| 15 | -1220016041512187680 |
| 16 | 21892299583455516896 |
| 17 | -392841376460687116580 |