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 | 9 |
| 2 | 320 |
| 3 | 7073 |
| 4 | 69632 |
| 5 | 423393 |
| 6 | 1941760 |
| 7 | 7861953 |
| 8 | 33554432 |
| 9 | 177264449 |
| 10 | 1173741824 |
| 11 | 8804293473 |
| 12 | 69149458432 |
| 13 | 550571544609 |
| 14 | 4399522300160 |
| 15 | 35186934979457 |
| 16 | 281479271677952 |
| 17 | 2251806789442689 |
| 18 | 18014409529442560 |
| 19 | 144115205059418913 |