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 | 0 |
| 3 | 0 |
| 4 | 23790 |
| 5 | 1525056 |
| 6 | 44420480 |
| 7 | 768892800 |
| 8 | 9093033300 |
| 9 | 80361232640 |
| 10 | 564369691392 |
| 11 | 3290997166080 |
| 12 | 16459430933400 |
| 13 | 72362333294400 |
| 14 | 285055580709120 |
| 15 | 1021529151913088 |
| 16 | 3371180795232510 |
| 17 | 10348222578720000 |