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 | 0 |
| 3 | -2 |
| 4 | 6 |
| 5 | -6 |
| 6 | 12 |
| 7 | -22 |
| 8 | 48 |
| 9 | -94 |
| 10 | 160 |
| 11 | -318 |
| 12 | 622 |
| 13 | -1210 |
| 14 | 2268 |
| 15 | -4482 |
| 16 | 8678 |
| 17 | -16998 |
| 18 | 32632 |
| 19 | -64366 |
| 20 | 124674 |
| 21 | -245866 |
| 22 | 476108 |
| 23 | -940866 |
| 24 | 1829148 |
| 25 | -3617066 |
| 26 | 7040112 |
| 27 | -13937530 |
| 28 | 27186810 |
| 29 | -53857062 |
| 30 | 105196572 |
| 31 | -208546726 |
| 32 | 407944704 |
| 33 | -809175966 |
| 34 | 1584713040 |