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 | 2 |
| 2 | 7 |
| 3 | 34 |
| 4 | 211 |
| 5 | 1596 |
| 6 | 14259 |
| 7 | 147106 |
| 8 | 1722683 |
| 9 | 22591408 |
| 10 | 328161643 |
| 11 | 5232410646 |
| 12 | 90880495347 |
| 13 | 1708304787892 |
| 14 | 34557610000931 |
| 15 | 748647340991818 |
| 16 | 17294012137850443 |
| 17 | 424368973372593432 |
| 18 | 11024176183963527099 |
| 19 | 302260934814635426014 |
| 20 | 8722906492537092723395 |