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 | -3 |
| 2 | 15 |
| 3 | -105 |
| 4 | 873 |
| 5 | -8595 |
| 6 | 97335 |
| 7 | -1233225 |
| 8 | 17298225 |
| 9 | -266220675 |
| 10 | 4444840575 |
| 11 | -79989057225 |
| 12 | 1543271585625 |
| 13 | -31735822993875 |
| 14 | 692766164665575 |
| 15 | -15995714865755625 |
| 16 | 389241925213766625 |
| 17 | -9954282875453791875 |