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 | 3 |
| 1 | -7 |
| 2 | 21 |
| 3 | -70 |
| 4 | 245 |
| 5 | -882 |
| 6 | 3234 |
| 7 | -12005 |
| 8 | 44933 |
| 9 | -169099 |
| 10 | 638666 |
| 11 | -2417807 |
| 12 | 9167018 |
| 13 | -34790490 |
| 14 | 132119827 |
| 15 | -501941055 |
| 16 | 1907443237 |
| 17 | -7249766678 |
| 18 | 27557748813 |
| 19 | -104759610858 |
| 20 | 398257159370 |
| 21 | -1514069805269 |
| 22 | 5756205681709 |
| 23 | -21884262613787 |
| 24 | 83201447389466 |
| 25 | -316323894905207 |