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 | 3 |
| 2 | -5 |
| 3 | 13 |
| 4 | -30 |
| 5 | 61 |
| 6 | -119 |
| 7 | 234 |
| 8 | -467 |
| 9 | 937 |
| 10 | -1878 |
| 11 | 3757 |
| 12 | -7511 |
| 13 | 15018 |
| 14 | -30035 |
| 15 | 60073 |
| 16 | -120150 |
| 17 | 240301 |
| 18 | -480599 |
| 19 | 961194 |
| 20 | -1922387 |
| 21 | 3844777 |
| 22 | -7689558 |
| 23 | 15379117 |
| 24 | -30758231 |
| 25 | 61516458 |
| 26 | -123032915 |
| 27 | 246065833 |
| 28 | -492131670 |
| 29 | 984263341 |
| 30 | -1968526679 |
| 31 | 3937053354 |
| 32 | -7874106707 |