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 | 138 |
| 2 | 10476 |
| 3 | 683208 |
| 4 | 42315696 |
| 5 | 2570768928 |
| 6 | 155010407616 |
| 7 | 9318969502848 |
| 8 | 559578466388736 |
| 9 | 33585275183251968 |
| 10 | 2015370124337581056 |
| 11 | 120928294183739148288 |
| 12 | 7255843732407562776576 |
| 13 | 435354129897768445943808 |