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) |
|---|---|
| 3 | 0 |
| 4 | 0 |
| 5 | 720 |
| 6 | 0 |
| 7 | 0 |
| 8 | 3600 |
| 9 | 2400 |
| 10 | 4320 |
| 11 | 28800 |
| 12 | 35400 |
| 13 | 64800 |
| 14 | 284400 |
| 15 | 540000 |
| 16 | 1139400 |
| 17 | 3708000 |
| 18 | 8557200 |
| 19 | 19677600 |
| 20 | 55725120 |
| 21 | 140359200 |
| 22 | 346456800 |
| 23 | 935942400 |
| 24 | 2442469200 |
| 25 | 6282571680 |