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 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 9 |
| 5 | 30 |
| 6 | 110 |
| 7 | 436 |
| 8 | 1801 |
| 9 | 7657 |
| 10 | 33401 |
| 11 | 148847 |
| 12 | 674585 |
| 13 | 3100410 |
| 14 | 14422567 |
| 15 | 67792847 |
| 16 | 321546251 |
| 17 | 1537241148 |
| 18 | 7400926549 |
| 19 | 35854579015 |
| 20 | 174677578889 |
| 21 | 855312650751 |
| 22 | 4207291811538 |
| 23 | 20782253017825 |
| 24 | 103048079556241 |
| 25 | 512753419159803 |
| 26 | 2559639388956793 |