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 | -3 |
| 2 | 3 |
| 3 | 0 |
| 4 | -6 |
| 5 | 12 |
| 6 | -12 |
| 7 | 0 |
| 8 | 24 |
| 9 | -48 |
| 10 | 48 |
| 11 | 0 |
| 12 | -96 |
| 13 | 192 |
| 14 | -192 |
| 15 | 0 |
| 16 | 384 |
| 17 | -768 |
| 18 | 768 |
| 19 | 0 |
| 20 | -1536 |
| 21 | 3072 |
| 22 | -3072 |
| 23 | 0 |
| 24 | 6144 |
| 25 | -12288 |
| 26 | 12288 |
| 27 | 0 |
| 28 | -24576 |
| 29 | 49152 |
| 30 | -49152 |
| 31 | 0 |
| 32 | 98304 |
| 33 | -196608 |
| 34 | 196608 |
| 35 | 0 |
| 36 | -393216 |
| 37 | 786432 |
| 38 | -786432 |
| 39 | 0 |
| 40 | 1572864 |
| 41 | -3145728 |
| 42 | 3145728 |
| 43 | 0 |
| 44 | -6291456 |