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 | -2 |
| 2 | 3 |
| 3 | -7 |
| 4 | 14 |
| 5 | -27 |
| 6 | 55 |
| 7 | -110 |
| 8 | 219 |
| 9 | -439 |
| 10 | 878 |
| 11 | -1755 |
| 12 | 3511 |
| 13 | -7022 |
| 14 | 14043 |
| 15 | -28087 |
| 16 | 56174 |
| 17 | -112347 |
| 18 | 224695 |
| 19 | -449390 |
| 20 | 898779 |
| 21 | -1797559 |
| 22 | 3595118 |
| 23 | -7190235 |
| 24 | 14380471 |
| 25 | -28760942 |
| 26 | 57521883 |
| 27 | -115043767 |
| 28 | 230087534 |
| 29 | -460175067 |
| 30 | 920350135 |
| 31 | -1840700270 |
| 32 | 3681400539 |
| 33 | -7362801079 |