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) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | -1 |
| 3 | 8 |
| 4 | -29 |
| 5 | 142 |
| 6 | -707 |
| 7 | 3714 |
| 8 | -20106 |
| 9 | 111570 |
| 10 | -631046 |
| 11 | 3624898 |
| 12 | -21089378 |
| 13 | 124014048 |
| 14 | -735906537 |
| 15 | 4401187158 |
| 16 | -26501494072 |
| 17 | 160532592098 |
| 18 | -977574311830 |
| 19 | 5981088128586 |
| 20 | -36748815585834 |
| 21 | 226651808352306 |
| 22 | -1402726443269229 |
| 23 | 8708648263017666 |