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) |
|---|---|
| 5 | 2 |
| 6 | 12 |
| 7 | 30 |
| 8 | 240 |
| 9 | 720 |
| 10 | 60480 |
| 11 | 60480 |
| 12 | 7983360 |
| 13 | 1108800 |
| 14 | 518918400 |
| 15 | 21794572800 |
| 16 | 62270208000 |
| 17 | 87178291200 |
| 18 | 35568742809600 |
| 19 | 2 |
| 20 | 40548366802944000 |
| 21 | 304112751022080000 |
| 22 | 851515702861824000 |
| 23 | 2534272925184000 |
| 24 | 5170403347776995328000 |
| 25 | 51704033477769953280000 |