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 | -2 |
| 4 | 21 |
| 5 | -454 |
| 6 | 25285 |
| 7 | -3606504 |
| 8 | 1328522713 |
| 9 | -1270747453940 |
| 10 | 3169192850406441 |
| 11 | -20676520009454537480 |
| 12 | 353872602524737587995341 |
| 13 | -15925173912641846013871947522 |
| 14 | 1888348697181821236021540428910349 |
| 15 | -591053910458037676348857289166882470064 |