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 | 2 |
| 4 | 6 |
| 5 | 24 |
| 6 | 48 |
| 7 | 288 |
| 8 | 2016 |
| 9 | 16128 |
| 10 | 64512 |
| 11 | 645120 |
| 12 | 3870720 |
| 13 | 46448640 |
| 14 | 278691840 |
| 15 | 2229534720 |
| 16 | 33443020800 |
| 17 | 535088332800 |
| 18 | 4280706662400 |
| 19 | 77052719923200 |
| 20 | 924632639078400 |
| 21 | 11095591668940800 |
| 22 | 110955916689408000 |
| 23 | 2441030167166976000 |
| 24 | 34174422340337664000 |