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 | -1 |
| 2 | 1 |
| 3 | 1 |
| 4 | -3 |
| 5 | 5 |
| 6 | -3 |
| 7 | -3 |
| 8 | 13 |
| 9 | -19 |
| 10 | 13 |
| 11 | 13 |
| 12 | -51 |
| 13 | 77 |
| 14 | -51 |
| 15 | -51 |
| 16 | 205 |
| 17 | -307 |
| 18 | 205 |
| 19 | 205 |
| 20 | -819 |
| 21 | 1229 |
| 22 | -819 |
| 23 | -819 |
| 24 | 3277 |
| 25 | -4915 |
| 26 | 3277 |
| 27 | 3277 |
| 28 | -13107 |
| 29 | 19661 |
| 30 | -13107 |
| 31 | -13107 |
| 32 | 52429 |
| 33 | -78643 |
| 34 | 52429 |
| 35 | 52429 |
| 36 | -209715 |
| 37 | 314573 |
| 38 | -209715 |
| 39 | -209715 |
| 40 | 838861 |
| 41 | -1258291 |
| 42 | 838861 |
| 43 | 838861 |
| 44 | -3355443 |
| 45 | 5033165 |
| 46 | -3355443 |