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 | -5 |
| 3 | 44 |
| 4 | -383 |
| 5 | 3782 |
| 6 | -39653 |
| 7 | 434324 |
| 8 | -4910009 |
| 9 | 56862170 |
| 10 | -671131131 |
| 11 | 8043570088 |
| 12 | -97629201137 |
| 13 | 1197607836678 |
| 14 | -14824033357867 |
| 15 | 184923041147906 |
| 16 | -2322472423266102 |
| 17 | 29341825623660226 |
| 18 | -372652945642370654 |
| 19 | 4755048678561786946 |
| 20 | -60929667733382420198 |