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 | 24 |
| 2 | 320 |
| 3 | 3584 |
| 4 | 36864 |
| 5 | 360448 |
| 6 | 3407872 |
| 7 | 31457280 |
| 8 | 285212672 |
| 9 | 2550136832 |
| 10 | 22548578304 |
| 11 | 197568495616 |
| 12 | 1717986918400 |
| 13 | 14843406974976 |
| 14 | 127543348822016 |
| 15 | 1090715534753792 |
| 16 | 9288674231451648 |
| 17 | 78812993478983680 |
| 18 | 666532744850833408 |
| 19 | 5620492334958379008 |
| 20 | 47269781688880726016 |