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 | 4 |
| 2 | 21 |
| 3 | 143 |
| 4 | 1061 |
| 5 | 8363 |
| 6 | 68906 |
| 7 | 586081 |
| 8 | 5096876 |
| 9 | 45086079 |
| 10 | 404204977 |
| 11 | 3663002302 |
| 12 | 33489857205 |
| 13 | 308457624821 |
| 14 | 2858876213963 |
| 15 | 26639628671867 |
| 16 | 249393770611256 |
| 17 | 2344318816620308 |
| 18 | 22116397130086627 |
| 19 | 209317712988603747 |
| 20 | 1986761935284574233 |
| 21 | 18906449883457813088 |
| 22 | 180340017203297174362 |