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 | 1 |
| 2 | 4 |
| 3 | 19 |
| 4 | 101 |
| 5 | 578 |
| 6 | 3479 |
| 7 | 21714 |
| 8 | 139269 |
| 9 | 912354 |
| 10 | 6078832 |
| 11 | 41066002 |
| 12 | 280636657 |
| 13 | 1936569717 |
| 14 | 13475408847 |
| 15 | 94446518559 |
| 16 | 666149216744 |
| 17 | 4724705621702 |
| 18 | 33676421377532 |
| 19 | 241100485812034 |
| 20 | 1732999323835918 |
| 21 | 12501487280292424 |
| 22 | 90478497094713958 |
| 23 | 656788523782034248 |
| 24 | 4780725762185300389 |