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 | 0 |
| 1 | -1 |
| 2 | -1 |
| 3 | -2 |
| 4 | 0 |
| 5 | -5 |
| 6 | 19 |
| 7 | 354 |
| 8 | 125308 |
| 9 | 15702094855 |
| 10 | 246555782835417471015 |
| 11 | 60789754049585540423053668337098365130214 |
| 12 | 3695394197409101611007702673065886746062029284385286815035968423367078017175685784 |