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 | 6 |
| 2 | 48 |
| 3 | 324 |
| 4 | 3840 |
| 5 | 19800 |
| 6 | 186624 |
| 7 | 1365336 |
| 8 | 16515072 |
| 9 | 84768120 |
| 10 | 760320000 |
| 11 | 5632621632 |
| 12 | 64258375680 |
| 13 | 366369658200 |
| 14 | 3105655160832 |
| 15 | 20140520400000 |
| 16 | 280012271910912 |
| 17 | 1495522910085120 |
| 18 | 12824556668190720 |
| 19 | 95907982079387520 |
| 20 | 1080582572777472000 |
| 21 | 5688765822212629632 |