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 | 512 |
| 3 | 0 |
| 4 | 47872 |
| 5 | 92160 |
| 6 | 2671104 |
| 7 | 9246720 |
| 8 | 88632832 |
| 9 | 300627968 |
| 10 | 1708766720 |
| 11 | 5099440128 |
| 12 | 21224886528 |
| 13 | 55690063872 |
| 14 | 187789235712 |
| 15 | 440993452032 |
| 16 | 1275935628288 |
| 17 | 2731242852352 |
| 18 | 7030806944256 |
| 19 | 13931439616000 |