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 | 1 |
| 2 | 4 |
| 3 | 12 |
| 4 | 60 |
| 5 | 240 |
| 6 | 1740 |
| 7 | 10080 |
| 8 | 87360 |
| 9 | 735840 |
| 10 | 7514640 |
| 11 | 79833600 |
| 12 | 976686480 |
| 13 | 12454041600 |
| 14 | 175736040480 |
| 15 | 2616448554720 |
| 16 | 42011071502400 |
| 17 | 711374856192000 |
| 18 | 12830610027755520 |
| 19 | 243290200817664000 |
| 20 | 4870565189425615680 |
| 21 | 102182981410948838400 |
| 22 | 2249099140674523737600 |