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 | 0 |
| 2 | 144 |
| 3 | 3888 |
| 4 | 62208 |
| 5 | 777600 |
| 6 | 8398080 |
| 7 | 82301184 |
| 8 | 752467968 |
| 9 | 6530347008 |
| 10 | 54419558400 |
| 11 | 438984437760 |
| 12 | 3448023220224 |
| 13 | 26487087464448 |
| 14 | 199671890116608 |
| 15 | 1481082701414400 |
| 16 | 10833062044631040 |
| 17 | 78268873272459264 |
| 18 | 559392241329635328 |
| 19 | 3959619590588203008 |
| 20 | 27786804144478617600 |