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 | 10 |
| 2 | 120 |
| 3 | 1680 |
| 4 | 26880 |
| 5 | 483840 |
| 6 | 9676800 |
| 7 | 212889600 |
| 8 | 5109350400 |
| 9 | 132843110400 |
| 10 | 3719607091200 |
| 11 | 111588212736000 |
| 12 | 3570822807552000 |
| 13 | 121407975456768000 |
| 14 | 4370687116443648000 |
| 15 | 166086110424858624000 |
| 16 | 6643444416994344960000 |