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 | 1 |
| 3 | -2 |
| 4 | 4 |
| 5 | -2 |
| 6 | -5 |
| 7 | 14 |
| 8 | -5 |
| 9 | -26 |
| 10 | 64 |
| 11 | -26 |
| 12 | -101 |
| 13 | 254 |
| 14 | -101 |
| 15 | -410 |
| 16 | 1024 |
| 17 | -410 |
| 18 | -1637 |
| 19 | 4094 |
| 20 | -1637 |
| 21 | -6554 |
| 22 | 16384 |
| 23 | -6554 |
| 24 | -26213 |
| 25 | 65534 |
| 26 | -26213 |
| 27 | -104858 |
| 28 | 262144 |
| 29 | -104858 |
| 30 | -419429 |