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 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | 2 |
| 4 | -4 |
| 5 | 8 |
| 6 | -14 |
| 7 | 25 |
| 8 | -48 |
| 9 | 92 |
| 10 | -168 |
| 11 | 310 |
| 12 | -590 |
| 13 | 1117 |
| 14 | -2092 |
| 15 | 3945 |
| 16 | -7500 |
| 17 | 14264 |
| 18 | -27102 |
| 19 | 51627 |
| 20 | -98694 |
| 21 | 188934 |
| 22 | -361936 |
| 23 | 694565 |
| 24 | -1335466 |
| 25 | 2570965 |
| 26 | -4954744 |
| 27 | 9561045 |
| 28 | -18473140 |
| 29 | 35730392 |
| 30 | -69176558 |
| 31 | 134063535 |
| 32 | -260062168 |
| 33 | 504918960 |