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 | 1 |
| 3 | 2 |
| 4 | -1 |
| 5 | -1 |
| 6 | 1 |
| 7 | 4 |
| 8 | -3 |
| 9 | -25 |
| 10 | 5 |
| 11 | 1382 |
| 12 | -691 |
| 13 | -49 |
| 14 | 35 |
| 15 | 28936 |
| 16 | -3617 |
| 17 | -131601 |
| 18 | 43867 |
| 19 | 349222 |
| 20 | -1222277 |
| 21 | -9399643 |
| 22 | 854513 |
| 23 | 945456364 |
| 24 | -1181820455 |
| 25 | -111190339 |
| 26 | 76977927 |
| 27 | 332492454406 |
| 28 | -23749461029 |
| 29 | -43079206380025 |
| 30 | 8615841276005 |