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 | -1 |
| 3 | 4 |
| 4 | -12 |
| 5 | 26 |
| 6 | -14 |
| 7 | -236 |
| 8 | 1604 |
| 9 | -6577 |
| 10 | 17827 |
| 11 | -14064 |
| 12 | -186496 |
| 13 | 1437856 |
| 14 | -6416576 |
| 15 | 18733256 |
| 16 | -17358808 |
| 17 | -201270728 |
| 18 | 1652571996 |
| 19 | -7692333934 |
| 20 | 23375782030 |
| 21 | -23913813710 |
| 22 | -250917362258 |
| 23 | 2147925544190 |
| 24 | -10270145045142 |
| 25 | 32053993413694 |
| 26 | -35259817590134 |