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 | 1 |
| 4 | 5 |
| 5 | 36 |
| 6 | 234 |
| 7 | 1597 |
| 8 | 12459 |
| 9 | 111451 |
| 10 | 1116277 |
| 11 | 12298958 |
| 12 | 147655760 |
| 13 | 1919465237 |
| 14 | 26870436345 |
| 15 | 403044639709 |
| 16 | 6448695657957 |
| 17 | 109628096021612 |
| 18 | 1973308547820586 |
| 19 | 37492874766408001 |
| 20 | 749857477972731979 |
| 21 | 15747006284752049759 |
| 22 | 346434131946498886045 |