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 | 2 |
| 3 | 1 |
| 4 | 12 |
| 5 | 24 |
| 6 | 720 |
| 7 | 144 |
| 8 | 2016 |
| 9 | 40320 |
| 10 | 725760 |
| 11 | 3628800 |
| 12 | 47900160 |
| 13 | 239500800 |
| 14 | 276756480 |
| 15 | 17435658240 |
| 16 | 871782912000 |
| 17 | 4184557977600 |
| 18 | 711374856192000 |
| 19 | 43553562624000 |
| 20 | 57926238289920000 |
| 21 | 3649353012264960000 |
| 22 | 324386934423552000 |
| 23 | 1124000727777607680000 |