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 | 6 |
| 5 | 30 |
| 6 | 180 |
| 7 | 1260 |
| 8 | 1260 |
| 9 | 1260 |
| 10 | 12600 |
| 11 | 138600 |
| 12 | 138600 |
| 13 | 1801800 |
| 14 | 25225200 |
| 15 | 378378000 |
| 16 | 378378000 |
| 17 | 6432426000 |
| 18 | 6432426000 |
| 19 | 122216094000 |
| 20 | 122216094000 |
| 21 | 2566537974000 |
| 22 | 56463835428000 |
| 23 | 1298668214844000 |
| 24 | 1298668214844000 |
| 25 | 1298668214844000 |
| 26 | 33765373585944000 |