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 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 24 |
| 5 | 60 |
| 6 | 720 |
| 7 | 2520 |
| 8 | 40320 |
| 9 | 25920 |
| 10 | 3628800 |
| 11 | 19958400 |
| 12 | 479001600 |
| 13 | 3113510400 |
| 14 | 87178291200 |
| 15 | 59439744000 |
| 16 | 426995712000 |
| 17 | 177843714048000 |
| 18 | 582033973248000 |
| 19 | 60822550204416000 |
| 20 | 143111882833920000 |