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) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 3432 |
| 3 | 50160 |
| 4 | 54035520 |
| 5 | 1284433920 |
| 6 | 456335953920 |
| 7 | 8825233697280 |
| 8 | 641668847339520 |
| 9 | 227019837729484800 |
| 10 | 28897358537888096256 |
| 11 | 2600752842642898944 |
| 12 | 34366074253507451879424 |
| 13 | 132424388815310703820800 |