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 | 0 |
| 2 | 12 |
| 3 | 2484 |
| 4 | 1557792 |
| 5 | 2560572000 |
| 6 | 9326330280000 |
| 7 | 66250877823900000 |
| 8 | 834917902101803520000 |
| 9 | 17373747843395915811840000 |
| 10 | 564479089176417832085760000000 |
| 11 | 27382950623629177584815808000000000 |
| 12 | 1912097851374544604017590025267200000000 |
| 13 | 186429568131038636125345650494922854400000000 |