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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | -2 |
| 4 | -17 |
| 5 | -65 |
| 6 | -134 |
| 7 | 331 |
| 8 | 5797 |
| 9 | 41092 |
| 10 | 199621 |
| 11 | 500731 |
| 12 | -2996432 |
| 13 | -58995155 |
| 14 | -573624323 |
| 15 | -4065029714 |
| 16 | -19194210269 |
| 17 | 7657775035 |
| 18 | 1581081323122 |
| 19 | 24363365708815 |
| 20 | 260409006907921 |
| 21 | 2127851409822892 |
| 22 | 11143555796154673 |
| 23 | -27234657667343081 |