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 | 3 |
| 2 | 12 |
| 3 | 46 |
| 4 | 120 |
| 5 | 597 |
| 6 | 2035 |
| 7 | 6554 |
| 8 | 28560 |
| 9 | 86158 |
| 10 | 341525 |
| 11 | 1315911 |
| 12 | 3455641 |
| 13 | 17021162 |
| 14 | 58317492 |
| 15 | 186118929 |
| 16 | 815616479 |
| 17 | 2474152797 |
| 18 | 9719139348 |
| 19 | 37641223154 |
| 20 | 99498527400 |
| 21 | 485257533003 |
| 22 | 1671083125805 |
| 23 | 5284814079046 |
| 24 | 23290743888720 |
| 25 | 71041880304722 |
| 26 | 276564805068235 |