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 | -2 |
| 3 | -3 |
| 4 | 8 |
| 5 | 55 |
| 6 | 84 |
| 7 | -637 |
| 8 | -4992 |
| 9 | -10593 |
| 10 | 92060 |
| 11 | 1012099 |
| 12 | 3642000 |
| 13 | -18733585 |
| 14 | -354606084 |
| 15 | -2157876645 |
| 16 | 2003383424 |
| 17 | 175455790399 |
| 18 | 1766183783868 |
| 19 | 5436448194707 |
| 20 | -96997103373360 |
| 21 | -1770215099996721 |
| 22 | -13073420293290148 |
| 23 | 22275369715313131 |