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 | 0 |
| 3 | -4 |
| 4 | -33 |
| 5 | -283 |
| 6 | -2785 |
| 7 | -31291 |
| 8 | -395360 |
| 9 | -5544754 |
| 10 | -85427259 |
| 11 | -1433955817 |
| 12 | -26046643595 |
| 13 | -509070113635 |
| 14 | -10653941722236 |
| 15 | -237754202827284 |
| 16 | -5636787946661521 |
| 17 | -141514316248243499 |
| 18 | -3751121064314067653 |
| 19 | -104704135027419849139 |
| 20 | -3070176356776990397500 |