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 | 2 |
| 2 | 6 |
| 3 | 30 |
| 4 | 210 |
| 5 | 420 |
| 6 | 420 |
| 7 | 1260 |
| 8 | 126 |
| 9 | 3150 |
| 10 | 97650 |
| 11 | 830025 |
| 12 | 6640200 |
| 13 | 6640200 |
| 14 | 312089400 |
| 15 | 312089400 |
| 16 | 9050592600 |
| 17 | 72404740800 |
| 18 | 4851117633600 |
| 19 | 354131587252800 |
| 20 | 4603710634286400 |
| 21 | 4603710634286400 |
| 22 | 197959557274315200 |
| 23 | 15227658251870400 |
| 24 | 1477082850431428800 |
| 25 | 78285391072865726400 |