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 | 2 |
| 3 | 4 |
| 4 | 16 |
| 5 | 77 |
| 6 | 730 |
| 7 | 8578 |
| 8 | 132422 |
| 9 | 2394795 |
| 10 | 50031012 |
| 11 | 1179054376 |
| 12 | 30959574248 |
| 13 | 896082610429 |
| 14 | 28346986843640 |
| 15 | 973097619619654 |
| 16 | 36028798243701780 |
| 17 | 1431211529242786625 |
| 18 | 60719765604009463866 |
| 19 | 2740193429053744941868 |
| 20 | 131072000002841600036024 |