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) |
|---|---|
| 4 | 9 |
| 5 | 550 |
| 6 | 19760 |
| 7 | 586425 |
| 8 | 16271380 |
| 9 | 446964322 |
| 10 | 12516198870 |
| 11 | 362901875292 |
| 12 | 10984979930625 |
| 13 | 348559615602900 |
| 14 | 11613184968311010 |
| 15 | 406385382363237945 |
| 16 | 14927815613184463440 |
| 17 | 575018321453046128700 |
| 18 | 23197450399028711170020 |
| 19 | 978734324107274793589440 |
| 20 | 43125048817869336467480865 |