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 | 1 |
| 2 | 6 |
| 3 | 46 |
| 4 | 416 |
| 5 | 4256 |
| 6 | 48096 |
| 7 | 591536 |
| 8 | 7840576 |
| 9 | 111226816 |
| 10 | 1680157056 |
| 11 | 26918720896 |
| 12 | 455971214336 |
| 13 | 8143926373376 |
| 14 | 153013563734016 |
| 15 | 3017996904928256 |
| 16 | 62369444355076096 |
| 17 | 1348096649995841536 |
| 18 | 30426167700424728576 |
| 19 | 715935203128235401216 |