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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 44 |
| 6 | 249 |
| 7 | 1513 |
| 8 | 10002 |
| 9 | 68455 |
| 10 | 482571 |
| 11 | 3470782 |
| 12 | 25391403 |
| 13 | 188353848 |
| 14 | 1414150643 |
| 15 | 10728851795 |
| 16 | 82151290333 |
| 17 | 634203702080 |
| 18 | 4931994064073 |
| 19 | 38607981904156 |
| 20 | 304032521364835 |