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 | 40 |
| 6 | 720 |
| 7 | 1008 |
| 8 | 8064 |
| 9 | 72576 |
| 10 | 3628800 |
| 11 | 5702400 |
| 12 | 68428800 |
| 13 | 80870400 |
| 14 | 317011968 |
| 15 | 118879488000 |
| 16 | 1902071808000 |
| 17 | 2487324672000 |
| 18 | 44771844096000 |
| 19 | 50039119872000 |
| 20 | 1000782397440000 |
| 21 | 21016430346240000 |
| 22 | 5085976143790080000 |
| 23 | 6156707963535360000 |