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 | -3 |
| 2 | 8 |
| 3 | -23 |
| 4 | 65 |
| 5 | -184 |
| 6 | 521 |
| 7 | -1475 |
| 8 | 4176 |
| 9 | -11823 |
| 10 | 33473 |
| 11 | -94768 |
| 12 | 268305 |
| 13 | -759619 |
| 14 | 2150616 |
| 15 | -6088775 |
| 16 | 17238401 |
| 17 | -48804968 |
| 18 | 138175513 |
| 19 | -391199363 |
| 20 | 1107554720 |
| 21 | -3135683679 |
| 22 | 8877676161 |
| 23 | -25134274400 |
| 24 | 71159584801 |
| 25 | -201465394563 |
| 26 | 570384233128 |
| 27 | -1614858840183 |
| 28 | 4571951541185 |