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 | -1440 |
| 2 | 319680 |
| 3 | -73733760 |
| 4 | 17014849920 |
| 5 | -3926422987200 |
| 6 | 906079372542720 |
| 7 | -209091033317387520 |
| 8 | 48250806224270918400 |
| 9 | -11134577434408058898720 |
| 10 | 2569466177758810678838400 |
| 11 | -592941804710481150566417280 |
| 12 | 136829971461225574971638023680 |