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 | 9 |
| 2 | 624 |
| 3 | 19040 |
| 4 | 30222192 |
| 5 | 592704000 |
| 6 | 12040481088 |
| 7 | 128024064000 |
| 8 | 1024192512000 |
| 9 | 3456649728000 |