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) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | 12 |
| 5 | 6 |
| 6 | 180 |
| 7 | 10 |
| 8 | 560 |
| 9 | 1260 |
| 10 | 12600 |
| 11 | 1260 |
| 12 | 166320 |
| 13 | 13860 |
| 14 | 2522520 |
| 15 | 2702700 |
| 16 | 2882880 |
| 17 | 360360 |
| 18 | 110270160 |
| 19 | 2042040 |
| 20 | 775975200 |
| 21 | 162954792 |
| 22 | 56904848 |
| 23 | 2586584 |
| 24 | 1427794368 |
| 25 | 892371480 |
| 26 | 116008292400 |
| 27 | 120470149800 |
| 28 | 1124388064800 |