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 | 16 |
| 3 | 504 |
| 4 | 1680 |
| 5 | 27300 |
| 6 | 87360 |
| 7 | 1936480 |
| 8 | 24344320 |
| 9 | 1232431200 |
| 10 | 1369368000 |
| 11 | 46695448800 |
| 12 | 865988323200 |
| 13 | 34711698621600 |
| 14 | 37381829284800 |
| 15 | 1722234277764000 |
| 16 | 21126073807238400 |
| 17 | 157125173941335600 |
| 18 | 55455943744000800 |
| 19 | 5321529955232400 |
| 20 | 162446703896568000 |