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 | -2 |
| 3 | -3 |
| 4 | 0 |
| 5 | -5 |
| 6 | 6 |
| 7 | -9 |
| 8 | 0 |
| 9 | 2 |
| 10 | 10 |
| 11 | -15 |
| 12 | 0 |
| 13 | -25 |
| 14 | 18 |
| 15 | 3 |
| 16 | 0 |
| 17 | -11 |
| 18 | -4 |
| 19 | -21 |
| 20 | 0 |
| 21 | 19 |
| 22 | 30 |
| 23 | -45 |
| 24 | 0 |
| 25 | -24 |
| 26 | 50 |
| 27 | -60 |
| 28 | 0 |
| 29 | -125 |
| 30 | -6 |
| 31 | -81 |
| 32 | 0 |
| 33 | 77 |
| 34 | 22 |
| 35 | 57 |
| 36 | 0 |
| 37 | -55 |
| 38 | 42 |
| 39 | 87 |
| 40 | 0 |
| 41 | -77 |
| 42 | -38 |
| 43 | -105 |
| 44 | 0 |
| 45 | -78 |
| 46 | 90 |
| 47 | -135 |
| 48 | 0 |
| 49 | -40 |
| 50 | 48 |
| 51 | -81 |
| 52 | 0 |
| 53 | -245 |
| 54 | 120 |
| 55 | -75 |
| 56 | 0 |
| 57 | -217 |
| 58 | 250 |
| 59 | -375 |
| 60 | 0 |
| 61 | -625 |
| 62 | 162 |
| 63 | -150 |
| 64 | 0 |
| 65 | 233 |
| 66 | -154 |
| 67 | -39 |
| 68 | 0 |
| 69 | 205 |
| 70 | -114 |
| 71 | -99 |
| 72 | 0 |
| 73 | -91 |
| 74 | 110 |
| 75 | 174 |
| 76 | 0 |
| 77 | -5 |
| 78 | -174 |
| 79 | -189 |
| 80 | 0 |