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 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 9 |
| 5 | 44 |
| 6 | 245 |
| 7 | 1462 |
| 8 | 9157 |
| 9 | 59368 |
| 10 | 395033 |
| 11 | 2682282 |
| 12 | 18510561 |
| 13 | 129451492 |
| 14 | 915401757 |
| 15 | 6534282398 |
| 16 | 47020440413 |
| 17 | 340733200288 |
| 18 | 2484299720065 |
| 19 | 18211441554706 |
| 20 | 134145473550009 |
| 21 | 992385470273692 |
| 22 | 7370066147881413 |