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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | -2 |
| 4 | 3 |
| 5 | -6 |
| 6 | 6 |
| 7 | -12 |
| 8 | 10 |
| 9 | -20 |
| 10 | 15 |
| 11 | -30 |
| 12 | 21 |
| 13 | -42 |
| 14 | 28 |
| 15 | -56 |
| 16 | 36 |
| 17 | -72 |
| 18 | 45 |
| 19 | -90 |
| 20 | 55 |
| 21 | -110 |
| 22 | 66 |
| 23 | -132 |
| 24 | 78 |
| 25 | -156 |
| 26 | 91 |
| 27 | -182 |
| 28 | 105 |
| 29 | -210 |
| 30 | 120 |
| 31 | -240 |
| 32 | 136 |
| 33 | -272 |
| 34 | 153 |
| 35 | -306 |
| 36 | 171 |
| 37 | -342 |
| 38 | 190 |
| 39 | -380 |
| 40 | 210 |
| 41 | -420 |
| 42 | 231 |
| 43 | -462 |
| 44 | 253 |
| 45 | -506 |
| 46 | 276 |
| 47 | -552 |
| 48 | 300 |
| 49 | -600 |
| 50 | 325 |
| 51 | -650 |
| 52 | 351 |
| 53 | -702 |
| 54 | 378 |
| 55 | -756 |
| 56 | 406 |
| 57 | -812 |
| 58 | 435 |
| 59 | -870 |
| 60 | 465 |
| 61 | -930 |
| 62 | 496 |
| 63 | -992 |