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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 14 |
| 5 | 51 |
| 6 | 181 |
| 7 | 652 |
| 8 | 2356 |
| 9 | 8625 |
| 10 | 31791 |
| 11 | 118195 |
| 12 | 442261 |
| 13 | 1665299 |
| 14 | 6302903 |
| 15 | 23968090 |
| 16 | 91513682 |
| 17 | 350687935 |
| 18 | 1348198490 |
| 19 | 5198114444 |
| 20 | 20094107710 |
| 21 | 77860452105 |
| 22 | 302340714990 |
| 23 | 1176325327796 |
| 24 | 4584989069865 |
| 25 | 17900574971247 |
| 26 | 69993587545033 |
| 27 | 274071021159757 |
| 28 | 1074577571232370 |