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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 420 |
| 8 | 16800 |
| 9 | 763560 |
| 10 | 43142400 |
| 11 | 2979900000 |
| 12 | 247022123040 |
| 13 | 24219716320800 |
| 14 | 2774585262168720 |
| 15 | 367448041040780700 |
| 16 | 55728771791388696000 |
| 17 | 9599063849925363974160 |
| 18 | 1863895566816244057824000 |