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) |
|---|---|
| 1 | 1 |
| 2 | -1 |
| 3 | 6 |
| 4 | -17 |
| 5 | 30 |
| 6 | -48 |
| 7 | 170 |
| 8 | -645 |
| 9 | 1183 |
| 10 | -1270 |
| 11 | 5742 |
| 12 | -22604 |
| 13 | 33462 |
| 14 | -40868 |
| 15 | 240756 |
| 16 | -746637 |
| 17 | 1136690 |
| 18 | -1884529 |
| 19 | 6625110 |
| 20 | -23217030 |
| 21 | 46565244 |
| 22 | -46627416 |
| 23 | 225058682 |
| 24 | -975425316 |
| 25 | 1356970471 |
| 26 | -1583502622 |
| 27 | 9182205852 |
| 28 | -26257649200 |
| 29 | 44560482150 |
| 30 | -77433044928 |