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) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 0 |
| 3 | 0 |
| 4 | 12 |
| 5 | 312 |
| 6 | 13824 |
| 7 | 1147488 |
| 8 | 178672128 |
| 9 | 52666091712 |
| 10 | 29715982846848 |
| 11 | 32452221242518272 |
| 12 | 69259424722321036032 |
| 13 | 291060255757818125657088 |
| 14 | 2421848956937579216663491584 |
| 15 | 40050322614433939228627991906304 |
| 16 | 1319551659023608317386779165849208832 |