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 | 9 |
| 3 | 61 |
| 4 | 369 |
| 5 | 2101 |
| 6 | 11529 |
| 7 | 61741 |
| 8 | 325089 |
| 9 | 1690981 |
| 10 | 8717049 |
| 11 | 44633821 |
| 12 | 227363409 |
| 13 | 1153594261 |
| 14 | 5835080169 |
| 15 | 29443836301 |
| 16 | 148292923329 |
| 17 | 745759583941 |
| 18 | 3745977788889 |
| 19 | 18798608421181 |
| 20 | 94267920012849 |