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) |
|---|---|
| 1 | 1 |
| 2 | -511 |
| 3 | 19684 |
| 4 | -262655 |
| 5 | 1953126 |
| 6 | -10058524 |
| 7 | 40353608 |
| 8 | -134480383 |
| 9 | 387440173 |
| 10 | -998047386 |
| 11 | 2357947692 |
| 12 | -5170101020 |
| 13 | 10604499374 |
| 14 | -20620693688 |
| 15 | 38445332184 |
| 16 | -68853957119 |
| 17 | 118587876498 |
| 18 | -197981928403 |
| 19 | 322687697780 |
| 20 | -512998309530 |
| 21 | 794320419872 |
| 22 | -1204911270612 |
| 23 | 1801152661464 |
| 24 | -2647111858972 |