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 | 1 |
| 2 | 2 |
| 3 | 9 |
| 4 | 144 |
| 5 | 1800 |
| 6 | 64800 |
| 7 | 39690 |
| 8 | 12700800 |
| 9 | 171460800 |
| 10 | 17146080000 |
| 11 | 518668920000 |
| 12 | 2390026383360 |
| 13 | 3606379096320000 |
| 14 | 449813829104640000 |
| 15 | 139161153379248000000 |
| 16 | 4453156908135936000000 |