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 | -1 |
| 3 | -10 |
| 4 | -264 |
| 5 | -13392 |
| 6 | -1111680 |
| 7 | -137030400 |
| 8 | -23500108800 |
| 9 | -5351202662400 |
| 10 | -1562069156659200 |
| 11 | -568747270103040000 |
| 12 | -252681700853514240000 |
| 13 | -134539938778433126400000 |
| 14 | -84573370199475510312960000 |
| 15 | -61972704966344777143418880000 |
| 16 | -52361960516341326660973363200000 |