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 | 3 |
| 2 | 15 |
| 3 | 165 |
| 4 | 2805 |
| 5 | 81345 |
| 6 | 3335145 |
| 7 | 196773555 |
| 8 | 13970922405 |
| 9 | 1411063162905 |
| 10 | 150983758430835 |
| 11 | 20684774905024395 |
| 12 | 3082031460848634855 |
| 13 | 551683631491905639045 |
| 14 | 105371573614953977057595 |
| 15 | 20758200002145933480346215 |
| 16 | 4712111400487126900038590805 |