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 | 4 |
| 2 | 1 |
| 3 | 7 |
| 4 | -14 |
| 5 | 55 |
| 6 | -173 |
| 7 | 580 |
| 8 | -1907 |
| 9 | 6307 |
| 10 | -20822 |
| 11 | 68779 |
| 12 | -227153 |
| 13 | 750244 |
| 14 | -2477879 |
| 15 | 8183887 |
| 16 | -27029534 |
| 17 | 89272495 |
| 18 | -294847013 |
| 19 | 973813540 |
| 20 | -3216287627 |
| 21 | 10622676427 |
| 22 | -35084316902 |
| 23 | 115875627139 |
| 24 | -382711198313 |
| 25 | 1264009222084 |
| 26 | -4174738864559 |
| 27 | 13788225815767 |