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 | 1 |
| 6 | -1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 1 |
| 10 | 1 |
| 11 | -1 |
| 12 | 1 |
| 13 | 7 |
| 14 | 1 |
| 15 | -1 |
| 16 | 1 |
| 17 | 1 |
| 18 | 21 |
| 19 | 21 |
| 20 | 1 |
| 21 | 1 |
| 22 | -1 |
| 23 | 1 |
| 24 | 51 |
| 25 | 161 |
| 26 | 51 |
| 27 | 1 |
| 28 | -1 |
| 29 | 1 |
| 30 | 1 |
| 31 | 113 |
| 32 | 813 |
| 33 | 813 |
| 34 | 113 |
| 35 | 1 |
| 36 | 1 |
| 37 | -1 |
| 38 | 1 |
| 39 | 239 |
| 40 | 3361 |
| 41 | 7631 |
| 42 | 3361 |
| 43 | 239 |
| 44 | 1 |
| 45 | -1 |
| 46 | 1 |
| 47 | 1 |
| 48 | 493 |
| 49 | 12421 |
| 50 | 53833 |
| 51 | 53833 |
| 52 | 12421 |
| 53 | 493 |
| 54 | 1 |
| 55 | 1 |
| 56 | -1 |
| 57 | 1 |
| 58 | 1003 |
| 59 | 42865 |
| 60 | 320107 |
| 61 | 607009 |
| 62 | 320107 |
| 63 | 42865 |