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 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 4 |
| 6 | 24 |
| 7 | 24 |
| 8 | 192 |
| 9 | 1728 |
| 10 | 17280 |
| 11 | 17280 |
| 12 | 207360 |
| 13 | 207360 |
| 14 | 414720 |
| 15 | 6220800 |
| 16 | 99532800 |
| 17 | 696729600 |
| 18 | 12541132800 |
| 19 | 12541132800 |
| 20 | 250822656000 |
| 21 | 5267275776000 |
| 22 | 10534551552000 |
| 23 | 10534551552000 |
| 24 | 252829237248000 |
| 25 | 1264146186240000 |
| 26 | 12641461862400000 |
| 27 | 3754514173132800000 |