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 | 2 |
| 3 | 4 |
| 4 | 11 |
| 5 | 47 |
| 6 | 292 |
| 7 | 2368 |
| 8 | 23427 |
| 9 | 272263 |
| 10 | 3628872 |
| 11 | 54525252 |
| 12 | 911484163 |
| 13 | 16775498551 |
| 14 | 337021458884 |
| 15 | 7338279413680 |
| 16 | 172130372061035 |
| 17 | 4327036966579151 |
| 18 | 116046966039565672 |
| 19 | 3307263639537314116 |