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 | 0 |
| 2 | -1 |
| 3 | 0 |
| 4 | -3 |
| 5 | -6 |
| 6 | -38 |
| 7 | -186 |
| 8 | -1181 |
| 9 | -8094 |
| 10 | -61865 |
| 11 | -516702 |
| 12 | -4688020 |
| 13 | -45887352 |
| 14 | -481954769 |
| 15 | -5406249972 |
| 16 | -64506680939 |
| 17 | -815807306442 |
| 18 | -10901200843386 |
| 19 | -153475188129114 |
| 20 | -2270769144678657 |
| 21 | -35226976789341426 |
| 22 | -571781884343282417 |
| 23 | -9691701188493783546 |