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 | 2 |
| 2 | 10 |
| 3 | 60 |
| 4 | 348 |
| 5 | 2030 |
| 6 | 11830 |
| 7 | 68952 |
| 8 | 401880 |
| 9 | 2342330 |
| 10 | 13652098 |
| 11 | 79570260 |
| 12 | 463769460 |
| 13 | 2703046502 |
| 14 | 15754509550 |
| 15 | 91824010800 |
| 16 | 535189555248 |
| 17 | 3119313320690 |
| 18 | 18180690368890 |
| 19 | 105964828892652 |
| 20 | 617608282987020 |