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 | -4 |
| 3 | -24 |
| 4 | -48 |
| 5 | -160 |
| 6 | -448 |
| 7 | -896 |
| 8 | -2304 |
| 9 | -5632 |
| 10 | -11264 |
| 11 | -26624 |
| 12 | -61440 |
| 13 | -122880 |
| 14 | -278528 |
| 15 | -622592 |
| 16 | -1245184 |
| 17 | -2752512 |
| 18 | -6029312 |
| 19 | -12058624 |
| 20 | -26214400 |
| 21 | -56623104 |
| 22 | -113246208 |
| 23 | -243269632 |
| 24 | -520093696 |
| 25 | -1040187392 |
| 26 | -2214592512 |