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 | 6 |
| 2 | -24 |
| 3 | 156 |
| 4 | -924 |
| 5 | 5556 |
| 6 | -33324 |
| 7 | 199956 |
| 8 | -1199724 |
| 9 | 7198356 |
| 10 | -43190124 |
| 11 | 259140756 |
| 12 | -1554844524 |
| 13 | 9329067156 |
| 14 | -55974402924 |
| 15 | 335846417556 |
| 16 | -2015078505324 |
| 17 | 12090471031956 |
| 18 | -72542826191724 |
| 19 | 435256957150356 |