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 | 1 |
| 2 | -14 |
| 3 | -7 |
| 4 | 1222 |
| 5 | -14873 |
| 6 | 26196 |
| 7 | 3522955 |
| 8 | -110841786 |
| 9 | 2088947819 |
| 10 | -15869398244 |
| 11 | -823790768205 |
| 12 | 55262757020956 |
| 13 | -2199333670723343 |
| 14 | 65894251730104552 |
| 15 | -1235877788883794355 |
| 16 | -18904175519674543546 |
| 17 | 3743957841955101437667 |
| 18 | -268850524243738610546292 |
| 19 | 14826380281246309472525851 |