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 | -1 |
| 3 | 2 |
| 4 | 3 |
| 5 | 14 |
| 6 | -40 |
| 7 | -43 |
| 8 | -357 |
| 9 | -1762 |
| 10 | 8004 |
| 11 | 13067 |
| 12 | 78540 |
| 13 | 492439 |
| 14 | 3932305 |
| 15 | -26867293 |
| 16 | -44643557 |
| 17 | -363632466 |
| 18 | -1729625764 |
| 19 | -15939972937 |
| 20 | -145669871232 |
| 21 | 1488599170613 |
| 22 | 3515325612655 |
| 23 | 26765194180353 |
| 24 | 151925998229148 |