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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 12 |
| 5 | 150 |
| 6 | 2160 |
| 7 | 36015 |
| 8 | 688128 |
| 9 | 14880348 |
| 10 | 360000000 |
| 11 | 9646149645 |
| 12 | 283787919360 |
| 13 | 9098660462034 |
| 14 | 315866083233792 |
| 15 | 11806916748046875 |
| 16 | 472877960873902080 |
| 17 | 20205339187128111480 |
| 18 | 917543123840934346752 |
| 19 | 44131536275846038655193 |