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 | 0 |
| 2 | -24 |
| 3 | 48 |
| 4 | 288 |
| 5 | -2880 |
| 6 | 3072 |
| 7 | 64512 |
| 8 | -400896 |
| 9 | -245760 |
| 10 | 12496896 |
| 11 | -50688000 |
| 12 | -159547392 |
| 13 | 2133540864 |
| 14 | -4964253696 |
| 15 | -42047373312 |
| 16 | 313193005056 |
| 17 | -179042254848 |
| 18 | -8158768005120 |
| 19 | 36487616790528 |
| 20 | 65397155954688 |
| 21 | -1204277276049408 |
| 22 | 2427936640598016 |
| 23 | 19127143199932416 |
| 24 | -107713462133587968 |
| 25 | -223101299070074880 |