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 | 5 |
| 2 | 20 |
| 3 | 240 |
| 4 | 3600 |
| 5 | 74880 |
| 6 | 1857600 |
| 7 | 56246400 |
| 8 | 1965600000 |
| 9 | 78744960000 |
| 10 | 3542608742400 |
| 11 | 177187481856000 |
| 12 | 9744664849920000 |
| 13 | 584718747604992000 |
| 14 | 38006232139459584000 |
| 15 | 2660470029606445056000 |