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 | 144 |
| 3 | 518400 |
| 4 | 2073600 |
| 5 | 406425600 |
| 6 | 3657830400 |
| 7 | 14631321600 |
| 8 | 58525286400 |
| 9 | 526727577600 |
| 10 | 2106910310400 |
| 11 | 13168189440000 |
| 12 | 52672757760000 |
| 13 | 210691031040000 |
| 14 | 842764124160000 |
| 15 | 1769804660736000 |
| 16 | 1896219279360000 |
| 17 | 7584877117440000 |
| 18 | 30339508469760000 |