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 | 1 |
| 2 | 4 |
| 3 | 18 |
| 4 | 96 |
| 5 | 2880 |
| 6 | 518400 |
| 7 | 181440 |
| 8 | 135475200 |
| 9 | 8778792960 |
| 10 | 376233984000 |
| 11 | 72425041920000 |
| 12 | 4588850656051200 |
| 13 | 47345284546560000 |
| 14 | 217144413044342784000 |
| 15 | 42750306318104985600000 |
| 16 | 4974581098834034688000000 |
| 17 | 70875936417673484697600000 |
| 18 | 13663463022599094380003328000000 |