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) |
|---|---|
| 2 | 1 |
| 3 | 1 |
| 4 | -1 |
| 5 | 1 |
| 6 | -1 |
| 7 | 1 |
| 8 | 1 |
| 9 | -1 |
| 10 | 1 |
| 11 | -1 |
| 12 | 1 |
| 13 | -5 |
| 14 | 17 |
| 15 | -5 |
| 16 | 5 |
| 17 | 1 |
| 18 | -5 |
| 19 | 41 |
| 20 | -236 |
| 21 | 691 |
| 22 | -691 |
| 23 | 1 |
| 24 | -7 |
| 25 | 14 |
| 26 | -22 |
| 27 | 359 |
| 28 | -7 |
| 29 | 7 |
| 30 | 1 |
| 31 | -14 |
| 32 | 77 |
| 33 | -293 |
| 34 | 1519 |
| 35 | -1237 |
| 36 | 3617 |
| 37 | -3617 |
| 38 | 1 |
| 39 | -6 |
| 40 | 217 |
| 41 | -1129 |
| 42 | 8487 |
| 43 | -6583 |
| 44 | 750167 |
| 45 | -43867 |
| 46 | 43867 |
| 47 | 1 |
| 48 | -5 |
| 49 | 23 |
| 50 | -470 |
| 51 | 689 |
| 52 | -28399 |
| 53 | 1540967 |
| 54 | -1254146 |
| 55 | 174611 |
| 56 | -174611 |