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 | -7 |
| 3 | 16 |
| 4 | -52 |
| 5 | 412 |
| 6 | -2068 |
| 7 | 6964 |
| 8 | -19960 |
| 9 | 81880 |
| 10 | -396844 |
| 11 | 1448908 |
| 12 | -3853348 |
| 13 | 9668860 |
| 14 | -45544768 |
| 15 | 238303744 |
| 16 | -764868256 |
| 17 | 1962327904 |
| 18 | -9820441204 |
| 19 | 62744531956 |
| 20 | -306405293056 |
| 21 | 1228176071080 |
| 22 | -5276516025688 |
| 23 | 26307346186816 |
| 24 | -126143746044604 |
| 25 | 534479888324932 |