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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 120 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 181440 |
| 10 | 1814400 |
| 11 | 0 |
| 12 | 0 |
| 13 | 1037836800 |
| 14 | 43589145600 |
| 15 | 217945728000 |
| 16 | 0 |
| 17 | 14820309504000 |
| 18 | 1867358997504000 |
| 19 | 30411275102208000 |
| 20 | 101370917007360000 |
| 21 | 425757851430912000 |
| 22 | 140500090972200960000 |
| 23 | 5385836820601036800000 |