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 | 7 |
| 3 | 41 |
| 4 | 231 |
| 5 | 1289 |
| 6 | 7175 |
| 7 | 39913 |
| 8 | 221991 |
| 9 | 1234633 |
| 10 | 6866503 |
| 11 | 38188457 |
| 12 | 212387175 |
| 13 | 1181202569 |
| 14 | 6569320583 |
| 15 | 36535623529 |
| 16 | 203194800039 |
| 17 | 1130078612041 |
| 18 | 6284991883975 |
| 19 | 34954314291497 |
| 20 | 194400264968679 |
| 21 | 1081167340448777 |