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) |
|---|---|
| 1 | 0 |
| 2 | 12 |
| 3 | -15 |
| 4 | 20 |
| 5 | -32 |
| 6 | 30 |
| 7 | 66 |
| 8 | -96 |
| 9 | -160 |
| 10 | 255 |
| 11 | -960 |
| 12 | -5280 |
| 13 | -640320 |