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 | -5 |
| 2 | 29 |
| 3 | -201 |
| 4 | 1631 |
| 5 | -15173 |
| 6 | 159093 |
| 7 | -1854893 |
| 8 | 23788271 |
| 9 | -332613321 |
| 10 | 5033396573 |
| 11 | -81929955953 |
| 12 | 1426898945343 |
| 13 | -26468817431501 |
| 14 | 520884561854501 |
| 15 | -10836674357638293 |
| 16 | 237603001692915983 |
| 17 | -5475288709200573713 |
| 18 | 132276033079845108621 |