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 | 4 |
| 2 | 24 |
| 3 | 120 |
| 4 | 1680 |
| 5 | 18480 |
| 6 | 480480 |
| 7 | 8168160 |
| 8 | 155195040 |
| 9 | 3569485920 |
| 10 | 103515091680 |
| 11 | 6417935684160 |
| 12 | 237463620313920 |
| 13 | 9736008432870720 |
| 14 | 418648362613440960 |
| 15 | 19676473042831725120 |
| 16 | 1042853071270081431360 |
| 17 | 61528331204934804450240 |
| 18 | 7506456407002046142929280 |
| 19 | 502932579269137091576261760 |