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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 2 |
| 7 | 5 |
| 8 | 15 |
| 9 | 58 |
| 10 | 275 |
| 11 | 1505 |
| 12 | 9003 |
| 13 | 56931 |
| 14 | 372973 |
| 15 | 2506312 |
| 16 | 17165954 |
| 17 | 119398333 |
| 18 | 841244274 |
| 19 | 5993093551 |
| 20 | 43109340222 |
| 21 | 312747109787 |
| 22 | 2286190318744 |
| 23 | 16826338257708 |
| 24 | 124605344758149 |
| 25 | 927910207739261 |
| 26 | 6945172081954449 |
| 27 | 52225283886702922 |