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 | 4 |
| 3 | 18 |
| 4 | 576 |
| 5 | 1200 |
| 6 | 518400 |
| 7 | 1587600 |
| 8 | 180633600 |
| 9 | 1646023680 |
| 10 | 13168189440000 |
| 11 | 461039040000 |
| 12 | 229442532802560000 |
| 13 | 86553098311680000 |
| 14 | 3753113311877529600 |
| 15 | 834966920275488000000 |