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 | 1 |
| 3 | -4 |
| 4 | 1 |
| 5 | 8 |
| 6 | -139 |
| 7 | 16 |
| 8 | -571 |
| 9 | -8992 |
| 10 | 163879 |
| 11 | -334144 |
| 12 | 5246819 |
| 13 | 698752 |
| 14 | -534703531 |
| 15 | 23349012224 |
| 16 | -4483131259 |
| 17 | -1357305243136 |
| 18 | 432261921612371 |
| 19 | -6319924923392 |
| 20 | 6232523202521089 |
| 21 | 8773495082018816 |
| 22 | -25834629665134204969 |
| 23 | 49004477022654464 |
| 24 | -1579029138854919086429 |