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) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 3 |
| 4 | 10 |
| 5 | 20 |
| 6 | 68 |
| 7 | 185 |
| 8 | 561 |
| 9 | 1588 |
| 10 | 4814 |
| 11 | 14322 |
| 12 | 42658 |
| 13 | 127606 |
| 14 | 381695 |
| 15 | 1142358 |
| 16 | 3419569 |
| 17 | 10243325 |
| 18 | 30685488 |
| 19 | 91937645 |
| 20 | 275496007 |
| 21 | 825602377 |
| 22 | 2474298468 |
| 23 | 7415685876 |
| 24 | 22226227933 |
| 25 | 66617647655 |
| 26 | 199673303891 |
| 27 | 598488700247 |