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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 720 |
| 7 | 10080 |
| 8 | 120960 |
| 9 | 1451520 |
| 10 | 18144000 |
| 11 | 239500800 |
| 12 | 3353011200 |
| 13 | 49816166400 |
| 14 | 784604620800 |
| 15 | 13076743680000 |
| 16 | 230150688768000 |
| 17 | 4268249137152000 |
| 18 | 83230858174464000 |
| 19 | 1703031405723648000 |