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 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 24 |
| 5 | 1680 |
| 6 | 5317635 |
| 7 | 66314914699608 |
| 8 | 8947678119828215014722891024 |
| 9 | 178098260698995011212395018312912894502905113202338936835 |