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 | 0 |
| 3 | -1 |
| 4 | -1 |
| 5 | 1 |
| 6 | 4 |
| 7 | 1 |
| 8 | -15 |
| 9 | -19 |
| 10 | 56 |
| 11 | 151 |
| 12 | -185 |
| 13 | -1091 |
| 14 | 204 |
| 15 | 7841 |
| 16 | 6209 |
| 17 | -56519 |
| 18 | -112400 |
| 19 | 396271 |
| 20 | 1520271 |
| 21 | -2442439 |
| 22 | -19165420 |
| 23 | 7701409 |
| 24 | 237686449 |
| 25 | 145269541 |
| 26 | -2944654296 |
| 27 | -4833158329 |
| 28 | 36392001815 |
| 29 | 104056218421 |
| 30 | -441823808804 |
| 31 | -2002667085119 |
| 32 | 5066513855745 |
| 33 | 37109187217649 |