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 | -2 |
| 2 | 40 |
| 3 | -3680 |
| 4 | 880000 |
| 5 | -435776000 |
| 6 | 386949376000 |
| 7 | -560034421760000 |
| 8 | 1233482823823360000 |
| 9 | -3926150877331865600000 |
| 10 | 17346066637844488192000000 |
| 11 | -102987227337891283042304000000 |
| 12 | 800183462504065339211776000000000 |