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 | 5 |
| 3 | -32 |
| 4 | 294 |
| 5 | -3527 |
| 6 | 51589 |
| 7 | -894706 |
| 8 | 17978610 |
| 9 | -410803143 |
| 10 | 10517824035 |
| 11 | -298204099693 |
| 12 | 9273022031794 |
| 13 | -313755862498513 |
| 14 | 11474175971184267 |
| 15 | -450960476552715192 |
| 16 | 18954545423649435646 |
| 17 | -848383466771831169101 |
| 18 | 40285210722052785437974 |