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 | 6 |
| 4 | 12 |
| 5 | 168 |
| 6 | 240 |
| 7 | 14880 |
| 8 | 65280 |
| 9 | 4294901760 |
| 10 | 7608944640 |
| 11 | 1125874137169920 |
| 12 | 18446744069414584320 |