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 | 2 |
| 5 | -2 |
| 6 | -28 |
| 7 | -65 |
| 8 | 338 |
| 9 | 3262 |
| 10 | 4352 |
| 11 | -113082 |
| 12 | -879140 |
| 13 | 1145012 |
| 14 | 68641120 |
| 15 | 409571279 |
| 16 | -3075414734 |
| 17 | -67796919090 |
| 18 | -235926569056 |
| 19 | 6635196777226 |
| 20 | 98653814115636 |
| 21 | -51631812077716 |
| 22 | -17882630766156440 |
| 23 | -190179698567684014 |
| 24 | 1532579370407751292 |
| 25 | 62028205219536446948 |
| 26 | 405883930741148425152 |
| 27 | -11224575706163698420700 |
| 28 | -269584771812788695251352 |
| 29 | -338220005828087037972744 |