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) |
|---|---|
| 2 | -1 |
| 3 | -1 |
| 4 | 100 |
| 5 | 1425 |
| 6 | -1 |
| 7 | 389305 |
| 8 | 8946176 |
| 9 | 225331713 |
| 10 | 6210001000 |
| 11 | 186492227801 |
| 12 | 6073061476032 |
| 13 | 213404945384449 |
| 14 | 8054585122464440 |
| 15 | 325144322753909625 |
| 16 | 13983676842985394176 |