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 | 1 |
| 2 | 2 |
| 3 | 30 |
| 4 | 242880 |
| 5 | 23565900177211392000 |
| 6 | 2773739201349556936377871973938118055565107020522751759201737480601600000000000000 |