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 | 9 |
| 3 | -12 |
| 4 | -99 |
| 5 | 1107 |
| 6 | -7038 |
| 7 | 33345 |
| 8 | -113643 |
| 9 | 151593 |
| 10 | 1547469 |
| 11 | -17376120 |
| 12 | 112734378 |
| 13 | -544200660 |
| 14 | 1884830229 |
| 15 | -2551628817 |
| 16 | -26299018683 |
| 17 | 298555990425 |
| 18 | -1956243650733 |
| 19 | 9538198578972 |
| 20 | -33464928293199 |
| 21 | 47571625958796 |
| 22 | 452674080810576 |
| 23 | -5260288747038957 |
| 24 | 34841458485708282 |
| 25 | -171603777320158968 |