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 | 6 |
| 2 | 120 |
| 3 | 2016 |
| 4 | 31680 |
| 5 | 480480 |
| 6 | 7128576 |
| 7 | 104186880 |
| 8 | 1506244608 |
| 9 | 21596889600 |
| 10 | 307660953600 |
| 11 | 4359995228160 |
| 12 | 61522462310400 |
| 13 | 865005820084224 |
| 14 | 12124867905454080 |
| 15 | 169509237023047680 |
| 16 | 2364380454476316672 |
| 17 | 32913250644698726400 |
| 18 | 457355892992216924160 |
| 19 | 6345297974846973542400 |