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 | -12 |
| 3 | 168 |
| 4 | -2160 |
| 5 | 27936 |
| 6 | -361152 |
| 7 | 4669056 |
| 8 | -60362496 |
| 9 | 780378624 |
| 10 | -10088893440 |
| 11 | 130431264768 |
| 12 | -1686241898496 |
| 13 | 21800077959168 |
| 14 | -281835838291968 |
| 15 | 3643630995013632 |
| 16 | -47105601999667200 |
| 17 | 608990795936169984 |
| 18 | -7873156775230046208 |