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 | 1 |
| 2 | 1 |
| 3 | -1 |
| 4 | -7 |
| 5 | -19 |
| 6 | 1 |
| 7 | 211 |
| 8 | 1009 |
| 9 | 953 |
| 10 | -14239 |
| 11 | -105049 |
| 12 | -209879 |
| 13 | 1669669 |
| 14 | 18057313 |
| 15 | 56255291 |
| 16 | -294375199 |
| 17 | -4628130319 |
| 18 | -19929569471 |
| 19 | 70149241423 |
| 20 | 1652969810521 |
| 21 | 9226206209501 |
| 22 | -20236475188159 |
| 23 | -783908527648861 |
| 24 | -5452368869656367 |