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 | -4 |
| 2 | -12 |
| 3 | -80 |
| 4 | -700 |
| 5 | -7056 |
| 6 | -77616 |
| 7 | -906048 |
| 8 | -11042460 |
| 9 | -139053200 |
| 10 | -1796567344 |
| 11 | -23696871744 |
| 12 | -317933029232 |
| 13 | -4326899214400 |
| 14 | -59605244280000 |
| 15 | -829705000377600 |
| 16 | -11654762427179100 |
| 17 | -165021757273414800 |
| 18 | -2353088020380174000 |
| 19 | -33764531705178120000 |