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 | 3 |
| 3 | 11 |
| 4 | 49 |
| 5 | 257 |
| 6 | 1539 |
| 7 | 10299 |
| 8 | 75905 |
| 9 | 609441 |
| 10 | 5284451 |
| 11 | 49134923 |
| 12 | 487026929 |
| 13 | 5120905441 |
| 14 | 56878092067 |
| 15 | 664920021819 |
| 16 | 8155340557697 |
| 17 | 104652541401025 |
| 18 | 1401572711758403 |
| 19 | 19546873773314571 |
| 20 | 283314887789276721 |
| 21 | 4259997696504874817 |
| 22 | 66341623494636864963 |