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 | 324 |
| 3 | -2277 |
| 4 | 10584 |
| 5 | -36882 |
| 6 | 118395 |
| 7 | -406836 |
| 8 | 1347273 |
| 9 | -3870993 |
| 10 | 10536993 |
| 11 | -30432051 |
| 12 | 86382090 |
| 13 | -223153434 |
| 14 | 565228773 |
| 15 | -1490547915 |
| 16 | 3825187308 |
| 17 | -9277759872 |
| 18 | 22515299145 |
| 19 | -55438134588 |
| 20 | 132989193954 |