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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | -3 |
| 5 | -2 |
| 6 | -32 |
| 7 | -81 |
| 8 | -311 |
| 9 | -810 |
| 10 | -2515 |
| 11 | -6864 |
| 12 | -19944 |
| 13 | -55043 |
| 14 | -156023 |
| 15 | -433522 |
| 16 | -1217427 |
| 17 | -3391226 |
| 18 | -9488456 |
| 19 | -26462205 |
| 20 | -73933535 |
| 21 | -206293134 |
| 22 | -576040339 |
| 23 | -1607642688 |
| 24 | -4488069168 |
| 25 | -12526662167 |
| 26 | -34967630447 |