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 | 4 |
| 2 | 384 |
| 3 | 31500 |
| 4 | 2558976 |
| 5 | 207746836 |
| 6 | 16864848000 |
| 7 | 1369080572444 |
| 8 | 111141302329344 |
| 9 | 9022397309950500 |
| 10 | 732433860440996736 |
| 11 | 59458627396289740076 |
| 12 | 4826822683620921984000 |
| 13 | 391839136544897998002484 |
| 14 | 31809312044806091140235904 |
| 15 | 2582264604005182130741437500 |