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 | 2 |
| 2 | 4 |
| 3 | 14 |
| 4 | 222 |
| 5 | 616126 |
| 6 | 200253952527184 |
| 7 | 263735716028826576482466871188128 |
| 8 | 5609038300883759793482640992086670939164957990135057216103303119630336 |