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 | 1 |
| 3 | -3 |
| 4 | 4 |
| 5 | -5 |
| 6 | 6 |
| 7 | -9 |
| 8 | 13 |
| 9 | -16 |
| 10 | 20 |
| 11 | -27 |
| 12 | 36 |
| 13 | -44 |
| 14 | 54 |
| 15 | -69 |
| 16 | 88 |
| 17 | -107 |
| 18 | 130 |
| 19 | -162 |
| 20 | 200 |
| 21 | -240 |
| 22 | 288 |
| 23 | -351 |
| 24 | 426 |
| 25 | -507 |
| 26 | 602 |
| 27 | -723 |
| 28 | 864 |
| 29 | -1019 |
| 30 | 1200 |
| 31 | -1422 |
| 32 | 1681 |
| 33 | -1968 |
| 34 | 2300 |
| 35 | -2700 |
| 36 | 3160 |
| 37 | -3674 |
| 38 | 4266 |
| 39 | -4965 |
| 40 | 5768 |
| 41 | -6665 |
| 42 | 7692 |
| 43 | -8892 |
| 44 | 10260 |
| 45 | -11792 |
| 46 | 13536 |
| 47 | -15552 |