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 | 3 |
| 4 | 9 |
| 5 | 35 |
| 6 | 150 |
| 7 | 672 |
| 8 | 3269 |
| 9 | 17271 |
| 10 | 97155 |
| 11 | 578985 |
| 12 | 3654750 |
| 13 | 24331320 |
| 14 | 170074177 |
| 15 | 1244911605 |
| 16 | 9520843575 |
| 17 | 75890001665 |
| 18 | 629104453236 |
| 19 | 5413637745144 |
| 20 | 48277814341765 |
| 21 | 445463898405225 |
| 22 | 4246785220234557 |
| 23 | 41775507558584283 |
| 24 | 423516880995944532 |