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 | 0 |
| 3 | 36 |
| 4 | 3456 |
| 5 | 77040 |
| 6 | 800640 |
| 7 | 5265540 |
| 8 | 25514496 |
| 9 | 99320256 |
| 10 | 327836160 |
| 11 | 951285060 |
| 12 | 2488844160 |
| 13 | 5980596336 |
| 14 | 13384215936 |
| 15 | 28197301860 |
| 16 | 56398325760 |
| 17 | 107825391360 |
| 18 | 198142765056 |
| 19 | 351580800996 |
| 20 | 604675808640 |
| 21 | 1011282960240 |
| 22 | 1649187872640 |
| 23 | 2628701385156 |