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 | 2 |
| 2 | -1 |
| 3 | -1 |
| 4 | -5 |
| 5 | 1 |
| 6 | 1 |
| 7 | 8 |
| 8 | -1 |
| 9 | -1 |
| 10 | -11 |
| 11 | 1 |
| 12 | 1 |
| 13 | 14 |
| 14 | -1 |
| 15 | -1 |
| 16 | -17 |
| 17 | 1 |
| 18 | 1 |
| 19 | 20 |
| 20 | -1 |
| 21 | -1 |
| 22 | -23 |
| 23 | 1 |
| 24 | 1 |
| 25 | 26 |
| 26 | -1 |
| 27 | -1 |
| 28 | -29 |
| 29 | 1 |
| 30 | 1 |
| 31 | 32 |
| 32 | -1 |
| 33 | -1 |
| 34 | -35 |
| 35 | 1 |
| 36 | 1 |
| 37 | 38 |
| 38 | -1 |
| 39 | -1 |
| 40 | -41 |
| 41 | 1 |
| 42 | 1 |
| 43 | 44 |
| 44 | -1 |
| 45 | -1 |
| 46 | -47 |
| 47 | 1 |
| 48 | 1 |
| 49 | 50 |
| 50 | -1 |
| 51 | -1 |
| 52 | -53 |
| 53 | 1 |
| 54 | 1 |
| 55 | 56 |
| 56 | -1 |
| 57 | -1 |
| 58 | -59 |
| 59 | 1 |
| 60 | 1 |
| 61 | 62 |
| 62 | -1 |
| 63 | -1 |
| 64 | -65 |
| 65 | 1 |
| 66 | 1 |
| 67 | 68 |
| 68 | -1 |
| 69 | -1 |