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 | -27 |
| 2 | 297 |
| 3 | -1548 |
| 4 | 2079 |
| 5 | 18036 |
| 6 | -88893 |
| 7 | 42471 |
| 8 | 632259 |
| 9 | -1042392 |
| 10 | -2491695 |
| 11 | 3171771 |
| 12 | 19897479 |
| 13 | -6178491 |
| 14 | -149788494 |
| 15 | 40753548 |
| 16 | 598051971 |
| 17 | 397032246 |
| 18 | -1758684468 |
| 19 | -5331986973 |
| 20 | 4009289778 |
| 21 | 22014953235 |