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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | 0 |
| 11 | 24 |
| 12 | -26 |
| 13 | 0 |
| 14 | 0 |
| 15 | 72 |
| 16 | 378 |
| 17 | -1080 |
| 18 | 665 |
| 19 | 384 |
| 20 | 1968 |
| 21 | 2016 |
| 22 | -25698 |
| 23 | 39552 |
| 24 | -3872 |
| 25 | 20880 |
| 26 | -65727 |
| 27 | -379072 |
| 28 | 1277646 |
| 29 | -986856 |
| 30 | 176978 |
| 31 | -2163504 |
| 32 | -1818996 |
| 33 | 27871080 |
| 34 | -47138844 |
| 35 | 20789424 |
| 36 | -36509652 |
| 37 | 77055330 |
| 38 | 393046656 |
| 39 | -1402934816 |
| 40 | 1403843388 |