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 | 2 |
| 3 | 20 |
| 4 | 1744 |
| 5 | 2002568 |
| 6 | 42263042752 |
| 7 | 21686691099024768 |
| 8 | 344069541824691045987328 |
| 9 | 226788686879114461294165127878656 |