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 | 0 |
| 2 | 520 |
| 3 | 22656 |
| 4 | 1795360 |
| 5 | 115363072 |
| 6 | 7876120608 |
| 7 | 527256809600 |
| 8 | 35522814546496 |
| 9 | 2388257605782016 |
| 10 | 160678147466414272 |
| 11 | 10807663334085120512 |
| 12 | 727010169682181839360 |
| 13 | 48903265220016072792320 |
| 14 | 3289569236212332037229184 |
| 15 | 221278350342281369716796672 |