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 | -3 |
| 2 | 3 |
| 3 | 21 |
| 4 | -63 |
| 5 | -423 |
| 6 | 1899 |
| 7 | 15201 |
| 8 | -72063 |
| 9 | -832491 |
| 10 | 3105459 |
| 11 | 60090093 |
| 12 | -110508543 |
| 13 | -5224722831 |
| 14 | -3828328677 |
| 15 | 510699368313 |
| 16 | 2104026859521 |
| 17 | -52582823289171 |
| 18 | -473592954347037 |
| 19 | 5168227121231301 |
| 20 | 92434892126557761 |
| 21 | -357595962971807223 |
| 22 | -17085974691782295477 |