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 | -1 |
| 2 | -2 |
| 3 | 5 |
| 4 | 12 |
| 5 | -41 |
| 6 | -89 |
| 7 | 391 |
| 8 | 733 |
| 9 | -4051 |
| 10 | -6320 |
| 11 | 44120 |
| 12 | 54990 |
| 13 | -496406 |
| 14 | -465932 |
| 15 | 5710408 |
| 16 | 3637847 |
| 17 | -66714699 |
| 18 | -22683218 |
| 19 | 787957397 |
| 20 | 35371351 |
| 21 | -9376925921 |
| 22 | 2356626520 |
| 23 | 112147043475 |
| 24 | -61910867756 |
| 25 | -1345231820826 |
| 26 | 1158452138826 |
| 27 | 16156200619772 |