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 | 0 |
| 3 | 8 |
| 4 | -16 |
| 5 | 64 |
| 6 | -192 |
| 7 | 640 |
| 8 | -2048 |
| 9 | 6656 |
| 10 | -21504 |
| 11 | 69632 |
| 12 | -225280 |
| 13 | 729088 |
| 14 | -2359296 |
| 15 | 7634944 |
| 16 | -24707072 |
| 17 | 79953920 |
| 18 | -258736128 |
| 19 | 837287936 |
| 20 | -2709520384 |
| 21 | 8768192512 |
| 22 | -28374466560 |
| 23 | 91821703168 |
| 24 | -297141272576 |
| 25 | 961569357824 |
| 26 | -3111703805952 |