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 | 54 |
| 4 | 6480 |
| 5 | 2268000 |
| 6 | 1837080000 |
| 7 | 2970558360000 |
| 8 | 8650265944320000 |
| 9 | 42040292489395200000 |
| 10 | 321608237543873280000000 |
| 11 | 3696886690566823353600000000 |
| 12 | 61486619437507406017075200000000 |
| 13 | 1433990938521547723130227814400000000 |