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 | 1 |
| 2 | -1 |
| 3 | 1 |
| 4 | 0 |
| 5 | -3 |
| 6 | 10 |
| 7 | -24 |
| 8 | 49 |
| 9 | -89 |
| 10 | 145 |
| 11 | -208 |
| 12 | 245 |
| 13 | -174 |
| 14 | -176 |
| 15 | 1121 |
| 16 | -3185 |
| 17 | 7137 |
| 18 | -13920 |
| 19 | 24301 |
| 20 | -37926 |
| 21 | 51256 |
| 22 | -53615 |
| 23 | 20407 |
| 24 | 97265 |
| 25 | -386224 |
| 26 | 984549 |
| 27 | -2083934 |
| 28 | 3896480 |
| 29 | -6537023 |
| 30 | 9734175 |
| 31 | -12231999 |
| 32 | 10690624 |
| 33 | 2126301 |
| 34 | -39992150 |
| 35 | 126414472 |
| 36 | -297132815 |
| 37 | 598577351 |
| 38 | -1075051951 |
| 39 | 1730868336 |
| 40 | -2443923755 |