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 | 0 |
| 3 | 6 |
| 4 | -2 |
| 5 | 38 |
| 6 | -32 |
| 7 | 314 |
| 8 | -436 |
| 9 | 3014 |
| 10 | -5732 |
| 11 | 31954 |
| 12 | -74934 |
| 13 | 363642 |
| 14 | -983868 |
| 15 | 4360230 |
| 16 | -13021586 |
| 17 | 54374950 |
| 18 | -173933428 |
| 19 | 698713298 |
| 20 | -2345075002 |
| 21 | 9189017010 |
| 22 | -31903354068 |
| 23 | 123070336590 |
| 24 | -437701811100 |
| 25 | 1672475509274 |
| 26 | -6052049207112 |
| 27 | 22998585552814 |