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 | 6 |
| 2 | 28 |
| 3 | 113 |
| 4 | 423 |
| 5 | 1507 |
| 6 | 5193 |
| 7 | 17469 |
| 8 | 57720 |
| 9 | 188098 |
| 10 | 606336 |
| 11 | 1937490 |
| 12 | 6146895 |
| 13 | 19386189 |
| 14 | 60836271 |
| 15 | 190104957 |
| 16 | 591899346 |
| 17 | 1837128933 |
| 18 | 5686494333 |
| 19 | 17559366768 |
| 20 | 54107166250 |
| 21 | 166412478896 |
| 22 | 510963917688 |
| 23 | 1566546588694 |