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 | -8 |
| 4 | -15 |
| 5 | 46 |
| 6 | 445 |
| 7 | 1240 |
| 8 | -4319 |
| 9 | -63782 |
| 10 | -282219 |
| 11 | 474508 |
| 12 | 16681489 |
| 13 | 119013142 |
| 14 | 137086573 |
| 15 | -6217558664 |
| 16 | -73971468351 |
| 17 | -333213031502 |
| 18 | 2327570156197 |
| 19 | 58209718600324 |
| 20 | 509023624616881 |
| 21 | 613709076338926 |
| 22 | -48850389688059651 |
| 23 | -773649504707845328 |