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 | -3 |
| 6 | 9 |
| 7 | 9 |
| 8 | -11 |
| 9 | -11 |
| 10 | 1 |
| 11 | 1 |
| 12 | 45 |
| 13 | 45 |
| 14 | -135 |
| 15 | -135 |
| 16 | 229 |
| 17 | 229 |
| 18 | -143 |
| 19 | -143 |
| 20 | -483 |
| 21 | -483 |
| 22 | 2025 |
| 23 | 2025 |
| 24 | -4139 |
| 25 | -4139 |
| 26 | 4321 |
| 27 | 4321 |
| 28 | 3597 |
| 29 | 3597 |
| 30 | -28071 |
| 31 | -28071 |
| 32 | 69829 |
| 33 | 69829 |
| 34 | -97199 |
| 35 | -97199 |
| 36 | 12285 |
| 37 | 12285 |
| 38 | 351945 |
| 39 | 351945 |
| 40 | -1104971 |
| 41 | -1104971 |
| 42 | 1907137 |
| 43 | 1907137 |
| 44 | -1301523 |
| 45 | -1301523 |
| 46 | -3723975 |
| 47 | -3723975 |