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 | -3 |
| 4 | -5 |
| 5 | -10 |
| 6 | -27 |
| 7 | -91 |
| 8 | -350 |
| 9 | -1459 |
| 10 | -6466 |
| 11 | -30258 |
| 12 | -149051 |
| 13 | -771157 |
| 14 | -4181702 |
| 15 | -23718221 |
| 16 | -140437759 |
| 17 | -866481074 |
| 18 | -5561061327 |
| 19 | -37066185842 |
| 20 | -256190732502 |
| 21 | -1833581728979 |
| 22 | -13571059095383 |
| 23 | -103744579461855 |
| 24 | -818183156375886 |
| 25 | -6649600332967494 |
| 26 | -55635988924348030 |