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 | 0 |
| 3 | -2 |
| 4 | 8 |
| 5 | -16 |
| 6 | 96 |
| 7 | -832 |
| 8 | 9344 |
| 9 | -27648 |
| 10 | 238080 |
| 11 | -4228608 |
| 12 | 55812096 |
| 13 | -398991360 |
| 14 | 4930609152 |
| 15 | -98606039040 |
| 16 | 2440552022016 |
| 17 | -17762113880064 |
| 18 | 235149341884416 |
| 19 | -7331825098948608 |
| 20 | 170578782435409920 |
| 21 | -2009778629489197056 |
| 22 | 38563016760590598144 |
| 23 | -1278044473427380666368 |