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 | -1 |
| 3 | 1 |
| 4 | -1 |
| 5 | 0 |
| 6 | 1 |
| 7 | -1 |
| 8 | -1 |
| 9 | 1 |
| 10 | 1 |
| 11 | -1 |
| 12 | -3 |
| 13 | 5 |
| 14 | 0 |
| 15 | 1 |
| 16 | -1 |
| 17 | -7 |
| 18 | 27 |
| 19 | 17 |
| 20 | -2 |
| 21 | 1 |
| 22 | -1 |
| 23 | -15 |
| 24 | 167 |
| 25 | 441 |
| 26 | -121 |
| 27 | 0 |
| 28 | 1 |
| 29 | -1 |
| 30 | -31 |
| 31 | 1071 |
| 32 | 10673 |
| 33 | -11529 |
| 34 | -721 |
| 35 | 5 |
| 36 | 1 |
| 37 | -1 |
| 38 | -63 |
| 39 | 6815 |
| 40 | 262305 |
| 41 | -1337713 |
| 42 | -442827 |
| 43 | 6845 |
| 44 | 0 |
| 45 | 1 |
| 46 | -1 |
| 47 | -127 |
| 48 | 42687 |
| 49 | 6525377 |
| 50 | -161721441 |
| 51 | -297209047 |
| 52 | 23444883 |
| 53 | 58337 |
| 54 | -14 |