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 | 3 |
| 3 | 56 |
| 4 | 2520 |
| 5 | 666624 |
| 6 | 839946240 |
| 7 | 3343877406720 |
| 8 | 41781748196966400 |
| 9 | 3701652434038082764800 |
| 10 | 763416952708225267547504640 |
| 11 | 750836199529096452135514747699200 |