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 | 0 |
| 2 | 5 |
| 3 | -23 |
| 4 | -283 |
| 5 | 2869 |
| 6 | 49781 |
| 7 | -776887 |
| 8 | -17600759 |
| 9 | 370643273 |
| 10 | 10387420489 |
| 11 | -275311670611 |
| 12 | -9201412118867 |
| 13 | 293959006143997 |
| 14 | 11414881932150269 |
| 15 | -426781883555301359 |
| 16 | -18884637964090410991 |
| 17 | 808793517812627212561 |
| 18 | 40173648337182874339601 |