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 | 6 |
| 2 | -14 |
| 3 | -684 |
| 4 | -2004 |
| 5 | 124776 |
| 6 | 1249656 |
| 7 | -29934864 |
| 8 | -616988784 |
| 9 | 8272012896 |
| 10 | 327277030176 |
| 11 | -2172344266944 |
| 12 | -193036432198464 |
| 13 | 145187966975616 |
| 14 | 126344808730855296 |
| 15 | 656437275502200576 |
| 16 | -90819982895128268544 |
| 17 | -1070069717772530072064 |
| 18 | 70776567154223847830016 |