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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 6 |
| 4 | 48 |
| 5 | 600 |
| 6 | 8640 |
| 7 | 131040 |
| 8 | 2257920 |
| 9 | 42819840 |
| 10 | 885427200 |
| 11 | 19918483200 |
| 12 | 483791616000 |
| 13 | 12622171161600 |
| 14 | 352200296448000 |
| 15 | 10466625641472000 |
| 16 | 330077933273088000 |
| 17 | 11010660024139776000 |
| 18 | 387369218691366912000 |
| 19 | 14335266857678807040000 |
| 20 | 556691771706962411520000 |