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 | 2 |
| 2 | 6 |
| 3 | 1 |
| 4 | 120 |
| 5 | 1 |
| 6 | 1512 |
| 7 | 1 |
| 8 | 17280 |
| 9 | 1 |
| 10 | 190080 |
| 11 | 1 |
| 12 | 1415232000 |
| 13 | 1 |
| 14 | 21772800 |
| 15 | 1 |
| 16 | 829108224000 |
| 17 | 1 |
| 18 | 105082151731200 |
| 19 | 1 |
| 20 | 4345502515200000 |
| 21 | 1 |
| 22 | 19989311569920000 |
| 23 | 1 |
| 24 | 626378114550988800000 |
| 25 | 1 |
| 26 | 17896517558599680000 |
| 27 | 1 |
| 28 | 944578196742891110400000 |