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 | 3 |
| 4 | 4 |
| 5 | 20 |
| 6 | 69 |
| 7 | 238 |
| 8 | 863 |
| 9 | 3264 |
| 10 | 12100 |
| 11 | 44861 |
| 12 | 166662 |
| 13 | 619591 |
| 14 | 2301800 |
| 15 | 8551800 |
| 16 | 31774561 |
| 17 | 118060082 |
| 18 | 438649107 |
| 19 | 1629796276 |
| 20 | 6055504952 |
| 21 | 22499207241 |
| 22 | 83595676570 |
| 23 | 310599326171 |
| 24 | 1154030334396 |
| 25 | 4287794153932 |
| 26 | 15931278338957 |