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 | 2 |
| 2 | -2 |
| 3 | 24 |
| 4 | -272 |
| 5 | 4840 |
| 6 | -107496 |
| 7 | 2934400 |
| 8 | -94501760 |
| 9 | 3511914624 |
| 10 | -147882696960 |
| 11 | 6959217277056 |
| 12 | -361941871760256 |
| 13 | 20616017227643136 |
| 14 | -1276341094954066176 |
| 15 | 85337532623368181760 |
| 16 | -6128269375791673718784 |
| 17 | 470426144496265208979456 |