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 | -6 |
| 3 | -486 |
| 4 | 839808 |
| 5 | 42515280000 |
| 6 | -80335512599040000 |
| 7 | -6890065294166289123840000 |
| 8 | 31601087581187838970614157148160000 |
| 9 | 8925080517850366815864624583251321642024960000 |