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 | 2 |
| 2 | -5 |
| 3 | -28 |
| 4 | -11 |
| 5 | 230 |
| 6 | 559 |
| 7 | -952 |
| 8 | -6935 |
| 9 | -5302 |
| 10 | 51811 |
| 11 | 151340 |
| 12 | -163619 |
| 13 | -1689298 |
| 14 | -1906025 |
| 15 | 11391632 |
| 16 | 39937489 |
| 17 | -22649710 |
| 18 | -404736821 |
| 19 | -605626252 |
| 20 | 2431378885 |
| 21 | 10313394038 |
| 22 | -1255621889 |