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 | 45 |
| 3 | -14589 |
| 4 | 17756793 |
| 5 | -58445425017 |
| 6 | 426876362998821 |
| 7 | -6061743911446054965 |
| 8 | 152244625648721441783409 |