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 | 1 |
| 2 | 2 |
| 3 | -4 |
| 4 | 0 |
| 5 | 16 |
| 6 | -48 |
| 7 | 96 |
| 8 | -160 |
| 9 | 256 |
| 10 | -448 |
| 11 | 896 |
| 12 | -1920 |
| 13 | 4096 |
| 14 | -8448 |
| 15 | 16896 |
| 16 | -33280 |
| 17 | 65536 |
| 18 | -130048 |
| 19 | 260096 |
| 20 | -522240 |
| 21 | 1048576 |
| 22 | -2101248 |
| 23 | 4202496 |
| 24 | -8396800 |
| 25 | 16777216 |
| 26 | -33538048 |
| 27 | 67076096 |
| 28 | -134184960 |
| 29 | 268435456 |
| 30 | -536936448 |
| 31 | 1073872896 |
| 32 | -2147614720 |
| 33 | 4294967296 |