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 | -2 |
| 3 | 7 |
| 4 | -26 |
| 5 | 103 |
| 6 | -442 |
| 7 | 1982 |
| 8 | -9122 |
| 9 | 42985 |
| 10 | -206526 |
| 11 | 1007322 |
| 12 | -4974066 |
| 13 | 24819268 |
| 14 | -124949782 |
| 15 | 633882799 |
| 16 | -3237261340 |
| 17 | 16629986395 |
| 18 | -85873762466 |
| 19 | 445491479309 |
| 20 | -2320717519612 |
| 21 | 12134813554225 |
| 22 | -63667883444468 |
| 23 | 335083404759136 |
| 24 | -1768545061282712 |
| 25 | 9358571746569760 |