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 | 6 |
| 2 | 36 |
| 3 | 180 |
| 4 | 1296 |
| 5 | 6000 |
| 6 | 41472 |
| 7 | 230496 |
| 8 | 1580800 |
| 9 | 8359200 |
| 10 | 58579200 |
| 11 | 310968900 |
| 12 | 2175102720 |
| 13 | 10971642240 |
| 14 | 76065091200 |
| 15 | 351048600000 |
| 16 | 2811459796992 |
| 17 | 14508487949472 |
| 18 | 88870766837760 |
| 19 | 522016066337712 |
| 20 | 3564233663616000 |
| 21 | 17479898551382400 |
| 22 | 128060205344805888 |