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 | 2520 |
| 8 | 13440 |
| 9 | 90720 |
| 10 | 725760 |
| 11 | 6652800 |
| 12 | 68428800 |
| 13 | 778377600 |
| 14 | 9686476800 |
| 15 | 130767436800 |
| 16 | 1902071808000 |
| 17 | 29640619008000 |
| 18 | 492490285056000 |
| 19 | 8688935743488000 |
| 20 | 162193467211776000 |
| 21 | 3193183885731840000 |
| 22 | 66117689869271040000 |
| 23 | 1436223152160276480000 |