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 | 1 |
| 3 | 2 |
| 4 | 5 |
| 5 | 12 |
| 6 | 33 |
| 7 | 90 |
| 8 | 261 |
| 9 | 766 |
| 10 | 2311 |
| 11 | 7065 |
| 12 | 21955 |
| 13 | 68921 |
| 14 | 218640 |
| 15 | 699161 |
| 16 | 2252410 |
| 17 | 7301482 |
| 18 | 23802026 |
| 19 | 77973162 |
| 20 | 256565366 |
| 21 | 847555502 |
| 22 | 2809934472 |
| 23 | 9346232579 |
| 24 | 31179372180 |
| 25 | 104298865434 |
| 26 | 349766936468 |
| 27 | 1175657140783 |
| 28 | 3960143985167 |
| 29 | 13366048810561 |