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 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 6 |
| 5 | 21 |
| 6 | 77 |
| 7 | 292 |
| 8 | 1143 |
| 9 | 4592 |
| 10 | 18821 |
| 11 | 78364 |
| 12 | 330512 |
| 13 | 1409149 |
| 14 | 6063526 |
| 15 | 26298592 |
| 16 | 114849110 |
| 17 | 504595293 |
| 18 | 2228824203 |
| 19 | 9891723114 |
| 20 | 44087704836 |
| 21 | 197255893945 |
| 22 | 885630834120 |
| 23 | 3988872011820 |
| 24 | 18017892014655 |