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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | -2 |
| 5 | 4 |
| 6 | -7 |
| 7 | 13 |
| 8 | -24 |
| 9 | 48 |
| 10 | -99 |
| 11 | 221 |
| 12 | -512 |
| 13 | 1268 |
| 14 | -3247 |
| 15 | 8773 |
| 16 | -24400 |
| 17 | 70896 |
| 18 | -211347 |
| 19 | 653541 |
| 20 | -2068472 |
| 21 | 6755684 |
| 22 | -22541135 |
| 23 | 77305981 |
| 24 | -270435640 |
| 25 | 969413776 |
| 26 | -3539893923 |
| 27 | 13212871629 |
| 28 | -50180362320 |
| 29 | 194412817844 |
| 30 | -765590169935 |
| 31 | 3070433223317 |