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 | 30 |
| 2 | -158 |
| 3 | -68220 |
| 4 | -1545108 |
| 5 | 242353800 |
| 6 | 15444235320 |
| 7 | -1075134862800 |
| 8 | -146634052663920 |
| 9 | 4700919898821600 |
| 10 | 1537277046430494240 |
| 11 | -3617421136617700800 |
| 12 | -17999352900456622989120 |
| 13 | -494053808263200360316800 |
| 14 | 232741485544984381782852480 |
| 15 | 14300169574344055190498016000 |