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) |
|---|---|
| 4 | 16 |
| 5 | 272 |
| 6 | 3968 |
| 7 | 56320 |
| 8 | 814080 |
| 9 | 12207360 |
| 10 | 191431680 |
| 11 | 3149752320 |
| 12 | 54428774400 |
| 13 | 987559372800 |
| 14 | 18797300121600 |
| 15 | 374883257548800 |
| 16 | 7822865085235200 |
| 17 | 170560590520320000 |
| 18 | 3879770715684864000 |
| 19 | 91945674412720128000 |