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 | 4 |
| 3 | -8 |
| 4 | 32 |
| 5 | -96 |
| 6 | 320 |
| 7 | -1024 |
| 8 | 3328 |
| 9 | -10752 |
| 10 | 34816 |
| 11 | -112640 |
| 12 | 364544 |
| 13 | -1179648 |
| 14 | 3817472 |
| 15 | -12353536 |
| 16 | 39976960 |
| 17 | -129368064 |
| 18 | 418643968 |
| 19 | -1354760192 |
| 20 | 4384096256 |
| 21 | -14187233280 |
| 22 | 45910851584 |
| 23 | -148570636288 |
| 24 | 480784678912 |
| 25 | -1555851902976 |
| 26 | 5034842521600 |
| 27 | -16293092655104 |