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 | 12 |
| 3 | 2880 |
| 4 | 226800 |
| 5 | 101606400 |
| 6 | 6985440000 |
| 7 | 35961045120000 |
| 8 | 1431699108840000 |
| 9 | 692306057963520000 |
| 10 | 181128033944995737600 |
| 11 | 344143264495491901440000 |
| 12 | 6651046563131624734080000 |
| 13 | 22028266217091941119272960000 |