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 | 17 |
| 3 | -433 |
| 4 | 20321 |
| 5 | -1584289 |
| 6 | 179967473 |
| 7 | -28151779537 |
| 8 | 5812048858049 |
| 9 | -1529741412486721 |
| 10 | 499975227342256337 |
| 11 | -198676311845589783793 |
| 12 | 94327947921149101192481 |
| 13 | -52736138158762405338195169 |
| 14 | 34291374178966525773142501553 |
| 15 | -25660133983889999165774819970577 |