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 | 0 |
| 3 | -3 |
| 4 | 21 |
| 5 | -100 |
| 6 | -525 |
| 7 | 33026 |
| 8 | -860503 |
| 9 | 16304464 |
| 10 | -100885935 |
| 11 | -12798492630 |
| 12 | 1037135603845 |
| 13 | -55556702499792 |
| 14 | 2207903148318777 |
| 15 | -31916679640973750 |
| 16 | -6164889702150516015 |
| 17 | 983802138243128355456 |
| 18 | -100629406324320358067423 |