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 | -3 |
| 3 | 0 |
| 4 | 4 |
| 5 | -9 |
| 6 | 105 |
| 7 | -308 |
| 8 | 36 |
| 9 | -423 |
| 10 | 2387 |
| 11 | -26004 |
| 12 | 104472 |
| 13 | -50617 |
| 14 | 119889 |
| 15 | -5466072 |
| 16 | 3154072 |
| 17 | 51692571 |
| 18 | -2921193 |
| 19 | 351666136 |
| 20 | -1278405156 |
| 21 | 11188330461 |
| 22 | -68445012691 |
| 23 | 553299094188 |
| 24 | -4915961459556 |