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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 6 |
| 4 | 120 |
| 5 | 4440 |
| 6 | 157680 |
| 7 | 9187920 |
| 8 | 557665920 |
| 9 | 50759291520 |
| 10 | 4795586208000 |
| 11 | 636749560339200 |
| 12 | 86796062772249600 |
| 13 | 15877174512431232000 |
| 14 | 2953945462595410483200 |
| 15 | 712801595188655900928000 |
| 16 | 173684063741850454560768000 |
| 17 | 53471242848053479728254976000 |
| 18 | 16530628080065352033845256192000 |