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 | 9 |
| 3 | 48 |
| 4 | 282 |
| 5 | 1762 |
| 6 | 11488 |
| 7 | 77270 |
| 8 | 532239 |
| 9 | 3735488 |
| 10 | 26617976 |
| 11 | 192061278 |
| 12 | 1400453568 |
| 13 | 10303466638 |
| 14 | 76391703591 |
| 15 | 570195719792 |
| 16 | 4281169118106 |
| 17 | 32312317899352 |
| 18 | 245016567557504 |
| 19 | 1865677590201192 |
| 20 | 14259825593908356 |