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 | 2 |
| 3 | 9 |
| 4 | 37 |
| 5 | 156 |
| 6 | 695 |
| 7 | 3203 |
| 8 | 15118 |
| 9 | 72739 |
| 10 | 355475 |
| 11 | 1759624 |
| 12 | 8804341 |
| 13 | 44457125 |
| 14 | 226256114 |
| 15 | 1159387253 |
| 16 | 5976713665 |
| 17 | 30974296468 |
| 18 | 161285018771 |
| 19 | 843388543471 |
| 20 | 4427120165182 |
| 21 | 23319497761799 |
| 22 | 123221525405447 |
| 23 | 652989260163472 |