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 | -2 |
| 2 | 2 |
| 3 | -6 |
| 4 | 14 |
| 5 | -26 |
| 6 | 50 |
| 7 | -102 |
| 8 | 214 |
| 9 | -426 |
| 10 | 834 |
| 11 | -1678 |
| 12 | 3398 |
| 13 | -6778 |
| 14 | 13482 |
| 15 | -27022 |
| 16 | 54198 |
| 17 | -108306 |
| 18 | 216346 |
| 19 | -432878 |
| 20 | 866334 |
| 21 | -1732386 |
| 22 | 3463626 |
| 23 | -6927926 |
| 24 | 13858350 |
| 25 | -27715378 |
| 26 | 55426002 |
| 27 | -110855030 |
| 28 | 221719582 |
| 29 | -443433610 |
| 30 | 886848930 |
| 31 | -1773709078 |
| 32 | 3547455846 |