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 | 2 |
| 3 | -4 |
| 4 | 72 |
| 5 | -2168 |
| 6 | 114864 |
| 7 | -10671216 |
| 8 | 1787642272 |
| 9 | -557621854080 |
| 10 | 332091938264960 |
| 11 | -383877081387120640 |
| 12 | 870132605833456937472 |
| 13 | -3891989736269204588784384 |
| 14 | 34485850497928703119235323904 |
| 15 | -606809291874393995479640098992128 |