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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 2 |
| 6 | 1 |
| 7 | 1 |
| 8 | 4 |
| 9 | 4 |
| 10 | -13 |
| 11 | -13 |
| 12 | 142 |
| 13 | 142 |
| 14 | -1931 |
| 15 | -1931 |
| 16 | 36296 |
| 17 | 36296 |
| 18 | -893273 |
| 19 | -893273 |
| 20 | 27927346 |
| 21 | 27927346 |
| 22 | -1081725559 |
| 23 | -1081725559 |
| 24 | 50861556172 |
| 25 | 50861556172 |
| 26 | -2854289486309 |
| 27 | -2854289486309 |