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) |
|---|---|
| 2 | 3 |
| 3 | -5 |
| 4 | 14 |
| 5 | -66 |
| 6 | 308 |
| 7 | -2132 |
| 8 | 14064 |
| 9 | -126480 |
| 10 | 1081632 |
| 11 | -11925792 |
| 12 | 125458560 |
| 13 | -1636387200 |
| 14 | 20447873280 |
| 15 | -307814964480 |