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 | 2 |
| 1 | 2 |
| 2 | 0 |
| 3 | 0 |
| 4 | 8 |
| 5 | 8 |
| 6 | -24 |
| 7 | -24 |
| 8 | 104 |
| 9 | 104 |
| 10 | -408 |
| 11 | -408 |
| 12 | 1640 |
| 13 | 1640 |
| 14 | -6552 |
| 15 | -6552 |
| 16 | 26216 |
| 17 | 26216 |
| 18 | -104856 |
| 19 | -104856 |
| 20 | 419432 |
| 21 | 419432 |
| 22 | -1677720 |
| 23 | -1677720 |
| 24 | 6710888 |
| 25 | 6710888 |
| 26 | -26843544 |
| 27 | -26843544 |
| 28 | 107374184 |
| 29 | 107374184 |
| 30 | -429496728 |
| 31 | -429496728 |
| 32 | 1717986920 |
| 33 | 1717986920 |