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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | -1 |
| 10 | 0 |
| 11 | 0 |
| 12 | 0 |
| 13 | 0 |
| 14 | 0 |
| 15 | 0 |
| 16 | 0 |
| 17 | -1 |
| 18 | 0 |
| 19 | 0 |
| 20 | 0 |
| 21 | 0 |
| 22 | 0 |
| 23 | 0 |
| 24 | 0 |
| 25 | -1 |
| 26 | 0 |
| 27 | 0 |
| 28 | 0 |
| 29 | 0 |
| 30 | 0 |
| 31 | 0 |
| 32 | 0 |
| 33 | -1 |
| 34 | 0 |
| 35 | 0 |
| 36 | -1 |
| 37 | 0 |
| 38 | 0 |
| 39 | 0 |
| 40 | 0 |
| 41 | -1 |
| 42 | 0 |
| 43 | 0 |
| 44 | -2 |
| 45 | 0 |
| 46 | 0 |
| 47 | 0 |
| 48 | 0 |
| 49 | -1 |
| 50 | 0 |
| 51 | 0 |
| 52 | -3 |
| 53 | 0 |
| 54 | 0 |
| 55 | 0 |
| 56 | 0 |
| 57 | -1 |
| 58 | 0 |
| 59 | 0 |
| 60 | -4 |
| 61 | 0 |
| 62 | 0 |
| 63 | -1 |
| 64 | 0 |
| 65 | -1 |
| 66 | 0 |
| 67 | 0 |
| 68 | -5 |
| 69 | 0 |
| 70 | 0 |
| 71 | -3 |
| 72 | 0 |
| 73 | -1 |
| 74 | 0 |
| 75 | 0 |
| 76 | -6 |
| 77 | 0 |
| 78 | 0 |
| 79 | -6 |
| 80 | 0 |
| 81 | -1 |