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) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | -1 |
| 4 | 9 |
| 5 | -1 |
| 6 | -1 |
| 7 | 16 |
| 8 | -4 |
| 9 | -1 |
| 10 | 0 |
| 11 | 25 |
| 12 | -4 |
| 13 | -1 |
| 14 | 0 |
| 15 | -1 |
| 16 | 36 |
| 17 | -9 |
| 18 | -4 |
| 19 | 0 |
| 20 | -1 |
| 21 | 1 |
| 22 | 49 |
| 23 | -9 |
| 24 | -4 |
| 25 | 0 |
| 26 | -1 |
| 27 | 1 |
| 28 | -1 |
| 29 | 64 |
| 30 | -16 |
| 31 | -4 |
| 32 | 0 |
| 33 | -1 |
| 34 | 1 |
| 35 | -1 |
| 36 | 0 |
| 37 | 81 |
| 38 | -16 |
| 39 | -9 |
| 40 | 0 |
| 41 | -1 |
| 42 | 1 |
| 43 | -1 |
| 44 | 0 |
| 45 | 0 |
| 46 | 100 |
| 47 | -25 |
| 48 | -9 |
| 49 | 0 |
| 50 | -4 |
| 51 | 1 |
| 52 | -1 |
| 53 | 0 |
| 54 | 0 |
| 55 | 1 |
| 56 | 121 |
| 57 | -25 |
| 58 | -9 |
| 59 | 0 |
| 60 | -4 |
| 61 | 1 |
| 62 | -1 |
| 63 | 0 |
| 64 | 0 |
| 65 | 1 |
| 66 | -1 |
| 67 | 144 |
| 68 | -36 |
| 69 | -16 |
| 70 | 0 |
| 71 | -4 |
| 72 | 4 |
| 73 | -1 |
| 74 | 0 |
| 75 | 0 |
| 76 | 1 |
| 77 | -1 |
| 78 | 0 |