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) |
|---|---|
| 3 | 2 |
| 4 | 8 |
| 5 | 40 |
| 6 | 240 |
| 7 | 1680 |
| 8 | 13440 |
| 9 | 120960 |
| 10 | 1209600 |
| 11 | 13305600 |
| 12 | 159667200 |
| 13 | 2075673600 |
| 14 | 29059430400 |
| 15 | 435891456000 |
| 16 | 6974263296000 |
| 17 | 118562476032000 |
| 18 | 2134124568576000 |
| 19 | 40548366802944000 |
| 20 | 810967336058880000 |
| 21 | 17030314057236480000 |
| 22 | 374666909259202560000 |