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 | 4 |
| 3 | -63 |
| 4 | 2288 |
| 5 | -138525 |
| 6 | 12381084 |
| 7 | -1528482823 |
| 8 | 249005711296 |
| 9 | -51739455340953 |
| 10 | 13353206066063900 |
| 11 | -4190486732316600771 |
| 12 | 1571373340568392914288 |
| 13 | -693899460077821703051125 |
| 14 | 356404409990391961980227068 |
| 15 | -210670220153918100996704166975 |