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 | 3 |
| 3 | 10 |
| 4 | 39 |
| 5 | 171 |
| 6 | 819 |
| 7 | 4229 |
| 8 | 23247 |
| 9 | 135088 |
| 10 | 824163 |
| 11 | 5255361 |
| 12 | 34876647 |
| 13 | 240130801 |
| 14 | 1710323667 |
| 15 | 12572548582 |
| 16 | 95183606559 |
| 17 | 740843916471 |
| 18 | 5918533467075 |
| 19 | 48463830575837 |
| 20 | 406239439253175 |
| 21 | 3481899731310196 |