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 | 1 |
| 4 | 7 |
| 5 | 39 |
| 6 | 239 |
| 7 | 1679 |
| 8 | 13439 |
| 9 | 120959 |
| 10 | 1209599 |
| 11 | 13305599 |
| 12 | 159667199 |
| 13 | 2075673599 |
| 14 | 29059430399 |
| 15 | 435891455999 |
| 16 | 6974263295999 |
| 17 | 118562476031999 |
| 18 | 2134124568575999 |
| 19 | 40548366802943999 |
| 20 | 810967336058879999 |