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 | 0 |
| 1 | 1 |
| 2 | -4 |
| 3 | -12 |
| 4 | 32 |
| 5 | 80 |
| 6 | -192 |
| 7 | -448 |
| 8 | 1024 |
| 9 | 2304 |
| 10 | -5120 |
| 11 | -11264 |
| 12 | 24576 |
| 13 | 53248 |
| 14 | -114688 |
| 15 | -245760 |
| 16 | 524288 |
| 17 | 1114112 |
| 18 | -2359296 |
| 19 | -4980736 |
| 20 | 10485760 |
| 21 | 22020096 |
| 22 | -46137344 |
| 23 | -96468992 |
| 24 | 201326592 |
| 25 | 419430400 |
| 26 | -872415232 |
| 27 | -1811939328 |
| 28 | 3758096384 |
| 29 | 7784628224 |
| 30 | -16106127360 |
| 31 | -33285996544 |