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 | 3 |
| 3 | -1 |
| 4 | -525 |
| 5 | 21599 |
| 6 | -575757 |
| 7 | -11712961 |
| 8 | 4147828275 |
| 9 | -478419026401 |
| 10 | 27474795508083 |
| 11 | 3849481231073279 |
| 12 | -1772585499434165325 |
| 13 | 366912253456842693599 |
| 14 | -26525609280231515934477 |
| 15 | -17189616925094873258825281 |
| 16 | 10414911263566240831226298675 |
| 17 | -3136992122810471155294591778401 |