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 | 5 |
| 3 | 1 |
| 4 | 1 |
| 5 | -1 |
| 6 | -1 |
| 7 | 1 |
| 8 | 1 |
| 9 | -1 |
| 10 | -1 |
| 11 | 1 |
| 12 | 691 |
| 13 | -691 |
| 14 | -1 |
| 15 | 2 |
| 16 | 3617 |
| 17 | -3617 |
| 18 | -43867 |
| 19 | 43867 |
| 20 | 174611 |
| 21 | -174611 |
| 22 | -77683 |
| 23 | 155366 |
| 24 | 236364091 |
| 25 | -236364091 |
| 26 | -657931 |
| 27 | 1315862 |
| 28 | 3392780147 |
| 29 | -6785560294 |
| 30 | -3446336510402 |
| 31 | 6892673020804 |
| 32 | 7709321041217 |
| 33 | -7709321041217 |
| 34 | -151628697551 |
| 35 | 151628697551 |