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 | -1 |
| 4 | 4 |
| 5 | -11 |
| 6 | 116 |
| 7 | -547 |
| 8 | 960 |
| 9 | -7751 |
| 10 | 414384 |
| 11 | -3258663 |
| 12 | -6813696 |
| 13 | -390445563 |
| 14 | 9694641984 |
| 15 | -964154427 |
| 16 | 208258646016 |
| 17 | -18431412645519 |
| 18 | 207842731632384 |
| 19 | -6436900596281679 |
| 20 | -37454668211552256 |
| 21 | 834261829219880829 |
| 22 | 91517388643567641600 |
| 23 | -1149793471388581053219 |