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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 40320 |
| 9 | 362880 |
| 10 | 3628800 |
| 11 | 36288000 |
| 12 | 402796800 |
| 13 | 4906137600 |
| 14 | 64988179200 |
| 15 | 929459059200 |
| 16 | 14266826784000 |
| 17 | 233845982899200 |
| 18 | 4075249496774400 |
| 19 | 75225258805132800 |
| 20 | 1465957162768492800 |
| 21 | 28530213421847558400 |
| 22 | 586170618419794464000 |