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 | 7 |
| 3 | 40 |
| 4 | 397 |
| 5 | 2336 |
| 6 | -46601 |
| 7 | -2661896 |
| 8 | -125428775 |
| 9 | -3724273664 |
| 10 | -90080842229 |
| 11 | 1096530753176 |
| 12 | 400257318802213 |
| 13 | 36023363702572000 |
| 14 | 2951479723885410943 |
| 15 | 178834401869241704056 |
| 16 | 8444450128124255913649 |
| 17 | -59239960097902788177664 |
| 18 | -92000068200778017857238125 |