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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 39 |
| 5 | 1525 |
| 6 | 2325630 |
| 7 | 5408554896906 |
| 8 | 29252466072845872288372843 |
| 9 | 855706771342998810018458679815602502067088579902657 |