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 | 0 |
| 2 | -1 |
| 3 | 3 |
| 4 | 0 |
| 5 | -6 |
| 6 | 10 |
| 7 | 3 |
| 8 | -28 |
| 9 | 33 |
| 10 | 27 |
| 11 | -120 |
| 12 | 100 |
| 13 | 168 |
| 14 | -487 |
| 15 | 252 |
| 16 | 891 |
| 17 | -1881 |
| 18 | 352 |
| 19 | 4302 |
| 20 | -6886 |
| 21 | -1365 |
| 22 | 19440 |
| 23 | -23595 |
| 24 | -16649 |
| 25 | 83280 |
| 26 | -73576 |
| 27 | -109632 |
| 28 | 340065 |
| 29 | -194376 |
| 30 | -595385 |
| 31 | 1324203 |
| 32 | -327808 |
| 33 | -2915982 |
| 34 | 4895802 |
| 35 | 608355 |
| 36 | -13315940 |
| 37 | 16995033 |
| 38 | 10245203 |
| 39 | -57551208 |
| 40 | 54055836 |
| 41 | 71291784 |