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 | 4 |
| 6 | -1 |
| 7 | 6 |
| 8 | -1 |
| 9 | -1 |
| 10 | 4 |
| 11 | -12 |
| 12 | -1 |
| 13 | -14 |
| 14 | 6 |
| 15 | 4 |
| 16 | -1 |
| 17 | 16 |
| 18 | -1 |
| 19 | 18 |
| 20 | 4 |
| 21 | 6 |
| 22 | -12 |
| 23 | -24 |
| 24 | -1 |
| 25 | -21 |
| 26 | -14 |
| 27 | -1 |
| 28 | 6 |
| 29 | 28 |
| 30 | 4 |
| 31 | 30 |
| 32 | -1 |
| 33 | -12 |
| 34 | 16 |
| 35 | -24 |
| 36 | -1 |
| 37 | -38 |
| 38 | 18 |
| 39 | -14 |
| 40 | 4 |
| 41 | 40 |
| 42 | 6 |
| 43 | 42 |
| 44 | -12 |
| 45 | 4 |
| 46 | -24 |
| 47 | -48 |
| 48 | -1 |
| 49 | -43 |
| 50 | -21 |
| 51 | 16 |
| 52 | -14 |
| 53 | 52 |
| 54 | -1 |
| 55 | 48 |
| 56 | 6 |
| 57 | 18 |
| 58 | 28 |
| 59 | -60 |
| 60 | 4 |
| 61 | -62 |
| 62 | 30 |
| 63 | 6 |