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 | 3 |
| 1 | -1 |
| 2 | 5 |
| 3 | -4 |
| 4 | 13 |
| 5 | -16 |
| 6 | 38 |
| 7 | -57 |
| 8 | 117 |
| 9 | -193 |
| 10 | 370 |
| 11 | -639 |
| 12 | 1186 |
| 13 | -2094 |
| 14 | 3827 |
| 15 | -6829 |
| 16 | 12389 |
| 17 | -22220 |
| 18 | 40169 |
| 19 | -72220 |
| 20 | 130338 |
| 21 | -234609 |
| 22 | 423065 |
| 23 | -761945 |
| 24 | 1373466 |
| 25 | -2474291 |
| 26 | 4459278 |
| 27 | -8034394 |
| 28 | 14478659 |
| 29 | -26088169 |
| 30 | 47011093 |
| 31 | -84708772 |
| 32 | 152642789 |
| 33 | -275049240 |