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 | -1 |
| 3 | 5 |
| 4 | -43 |
| 5 | 527 |
| 6 | -8396 |
| 7 | 164672 |
| 8 | -3835910 |
| 9 | 103464895 |
| 10 | -3170985454 |
| 11 | 108828369497 |
| 12 | -4134333957073 |
| 13 | 172223139437835 |
| 14 | -7805591781504739 |
| 15 | 382374360671653989 |
| 16 | -20132511625986242785 |
| 17 | 1133765691312312723347 |
| 18 | -68002260363248096548050 |