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 | -3 |
| 3 | 22 |
| 4 | -250 |
| 5 | 3810 |
| 6 | -72492 |
| 7 | 1649634 |
| 8 | -43626510 |
| 9 | 1313526375 |
| 10 | -44332221175 |
| 11 | 1657043432088 |
| 12 | -67929461003560 |
| 13 | 3029864359322346 |
| 14 | -146058681728370600 |
| 15 | 7566706624571096610 |
| 16 | -419220650458638848514 |
| 17 | 24733868801871384287055 |
| 18 | -1548237182318766914543100 |