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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 504 |
| 8 | 4032 |
| 9 | 27216 |
| 10 | 514080 |
| 11 | 4823280 |
| 12 | 57081024 |
| 13 | 500972472 |
| 14 | 4412103696 |
| 15 | 60619398840 |
| 16 | 686638592640 |
| 17 | 9335025764064 |
| 18 | 104304736815552 |
| 19 | 1180585704051936 |
| 20 | 29016515871665280 |
| 21 | 478096386437121480 |