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 | 1 |
| 3 | 8 |
| 4 | 48 |
| 5 | 120 |
| 6 | 2640 |
| 7 | 30240 |
| 8 | 201600 |
| 9 | 4838400 |
| 10 | 96163200 |
| 11 | 1037836800 |
| 12 | 30496435200 |
| 13 | 828193766400 |
| 14 | 13686991718400 |
| 15 | 450537408921600 |
| 16 | 15880397524992000 |
| 17 | 356398802952192000 |
| 18 | 13410127414075392000 |
| 19 | 569542360114151424000 |
| 20 | 16614774394239909888000 |