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 | 4 |
| 3 | 19 |
| 4 | 112 |
| 5 | 811 |
| 6 | 7024 |
| 7 | 70939 |
| 8 | 818752 |
| 9 | 10630891 |
| 10 | 153371344 |
| 11 | 2433948859 |
| 12 | 42137351392 |
| 13 | 790287522571 |
| 14 | 15962014455664 |
| 15 | 345424786466779 |
| 16 | 7973482022972032 |
| 17 | 195556150543703851 |
| 18 | 5078301994885267984 |