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 | 2 |
| 1 | 5 |
| 2 | 20 |
| 3 | 89 |
| 4 | 809 |
| 5 | 10704 |
| 6 | 145989 |
| 7 | 2054864 |
| 8 | 19686928 |
| 9 | 128199160 |