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 | 0 |
| 3 | 5 |
| 4 | -4 |
| 5 | 13 |
| 6 | -16 |
| 7 | 49 |
| 8 | -88 |
| 9 | 173 |
| 10 | -324 |
| 11 | 701 |
| 12 | -1384 |
| 13 | 2713 |
| 14 | -5416 |
| 15 | 10989 |
| 16 | -21916 |
| 17 | 43621 |
| 18 | -87224 |
| 19 | 174921 |
| 20 | -349872 |
| 21 | 698773 |
| 22 | -1397356 |
| 23 | 2796949 |
| 24 | -5593872 |
| 25 | 11183361 |
| 26 | -22366976 |
| 27 | 44742149 |
| 28 | -89483716 |
| 29 | 178951741 |
| 30 | -357903312 |
| 31 | 715838513 |
| 32 | -1431678040 |
| 33 | 2863290285 |