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 | -1 |
| 2 | 2 |
| 3 | -4 |
| 4 | 6 |
| 5 | -9 |
| 6 | 12 |
| 7 | -16 |
| 8 | 20 |
| 9 | -25 |
| 10 | 30 |
| 11 | -36 |
| 12 | 42 |
| 13 | -49 |
| 14 | 56 |
| 15 | -64 |
| 16 | 72 |
| 17 | -81 |
| 18 | 90 |
| 19 | -100 |
| 20 | 110 |
| 21 | -121 |
| 22 | 132 |
| 23 | -144 |
| 24 | 156 |
| 25 | -169 |
| 26 | 182 |
| 27 | -196 |
| 28 | 210 |
| 29 | -225 |
| 30 | 240 |
| 31 | -256 |
| 32 | 272 |
| 33 | -289 |
| 34 | 306 |
| 35 | -324 |
| 36 | 342 |
| 37 | -361 |
| 38 | 380 |
| 39 | -400 |
| 40 | 420 |
| 41 | -441 |
| 42 | 462 |
| 43 | -484 |
| 44 | 506 |
| 45 | -529 |
| 46 | 552 |
| 47 | -576 |
| 48 | 600 |
| 49 | -625 |
| 50 | 650 |
| 51 | -676 |
| 52 | 702 |