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 | -5 |
| 4 | -16 |
| 5 | -65 |
| 6 | -187 |
| 7 | -665 |
| 8 | -1984 |
| 9 | -6260 |
| 10 | -18895 |
| 11 | -58025 |
| 12 | -174016 |
| 13 | -527345 |
| 14 | -1583407 |
| 15 | -4765595 |
| 16 | -14307568 |
| 17 | -42981185 |
| 18 | -128980852 |
| 19 | -387158345 |
| 20 | -1161657760 |
| 21 | -3485726195 |
| 22 | -10458022927 |
| 23 | -31376865305 |
| 24 | -94134053296 |
| 25 | -282412754000 |
| 26 | -847252941535 |
| 27 | -2541798630320 |
| 28 | -7625456893096 |
| 29 | -22876524019505 |
| 30 | -68629821114805 |