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 | 5 |
| 3 | 31 |
| 4 | 219 |
| 5 | 1678 |
| 6 | 13570 |
| 7 | 114014 |
| 8 | 985542 |
| 9 | 8708099 |
| 10 | 78298727 |
| 11 | 714105907 |
| 12 | 6590200215 |
| 13 | 61427125994 |
| 14 | 577456943614 |
| 15 | 5468604044500 |
| 16 | 52122539760992 |
| 17 | 499613409224137 |
| 18 | 4813105582181533 |
| 19 | 46576519080852235 |
| 20 | 452545041339982871 |
| 21 | 4413071971740021275 |
| 22 | 43177663974461532959 |