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 | 2 |
| 5 | 1 |
| 6 | 1 |
| 7 | -3 |
| 8 | -1 |
| 9 | -1 |
| 10 | 4 |
| 11 | 1 |
| 12 | 1 |
| 13 | -5 |
| 14 | -1 |
| 15 | -1 |
| 16 | 6 |
| 17 | 1 |
| 18 | 1 |
| 19 | -7 |
| 20 | -1 |
| 21 | -1 |
| 22 | 8 |
| 23 | 1 |
| 24 | 1 |
| 25 | -9 |
| 26 | -1 |
| 27 | -1 |
| 28 | 10 |
| 29 | 1 |
| 30 | 1 |
| 31 | -11 |
| 32 | -1 |
| 33 | -1 |
| 34 | 12 |
| 35 | 1 |
| 36 | 1 |
| 37 | -13 |
| 38 | -1 |
| 39 | -1 |
| 40 | 14 |
| 41 | 1 |
| 42 | 1 |
| 43 | -15 |
| 44 | -1 |
| 45 | -1 |
| 46 | 16 |
| 47 | 1 |
| 48 | 1 |
| 49 | -17 |
| 50 | -1 |
| 51 | -1 |
| 52 | 18 |
| 53 | 1 |
| 54 | 1 |
| 55 | -19 |
| 56 | -1 |
| 57 | -1 |
| 58 | 20 |
| 59 | 1 |
| 60 | 1 |