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 | 1 |
| 2 | -1 |
| 3 | 5 |
| 4 | -85 |
| 5 | 3145 |
| 6 | -204425 |
| 7 | 20646925 |
| 8 | -2993804125 |
| 9 | 589779412625 |
| 10 | -151573309044625 |
| 11 | 49261325439503125 |
| 12 | -19753791501240753125 |
| 13 | 9580588878101765265625 |
| 14 | -5527999782664718558265625 |
| 15 | 3742455852864014463945828125 |
| 16 | -2937827844498251354197475078125 |
| 17 | 2646982887892924470131925045390625 |