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 | 0 |
| 2 | 12 |
| 3 | 240 |
| 4 | 9296 |
| 5 | 558720 |
| 6 | 47965632 |
| 7 | 5537249536 |
| 8 | 823842474240 |
| 9 | 153119256219648 |
| 10 | 34710583399132160 |
| 11 | 9416311849673895936 |
| 12 | 3009741915237844832256 |
| 13 | 1118809461121375449088000 |