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 | 1 |
| 2 | 5 |
| 3 | 21 |
| 4 | 125 |
| 5 | 791 |
| 6 | 5457 |
| 7 | 39019 |
| 8 | 288317 |
| 9 | 2178929 |
| 10 | 16773395 |
| 11 | 131034839 |
| 12 | 1036252649 |
| 13 | 8279446917 |
| 14 | 66733111919 |
| 15 | 541954722471 |
| 16 | 4430427981533 |
| 17 | 36428763143945 |
| 18 | 301074015186469 |
| 19 | 2499725665085301 |
| 20 | 20840038803521835 |
| 21 | 174388665638906551 |
| 22 | 1464205768804076875 |