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 | -3 |
| 2 | 4 |
| 3 | -4 |
| 4 | 6 |
| 5 | -12 |
| 6 | 20 |
| 7 | -28 |
| 8 | 40 |
| 9 | -64 |
| 10 | 104 |
| 11 | -160 |
| 12 | 240 |
| 13 | -368 |
| 14 | 576 |
| 15 | -896 |
| 16 | 1376 |
| 17 | -2112 |
| 18 | 3264 |
| 19 | -5056 |
| 20 | 7808 |
| 21 | -12032 |
| 22 | 18560 |
| 23 | -28672 |
| 24 | 44288 |
| 25 | -68352 |
| 26 | 105472 |
| 27 | -162816 |
| 28 | 251392 |
| 29 | -388096 |
| 30 | 599040 |
| 31 | -924672 |
| 32 | 1427456 |
| 33 | -2203648 |
| 34 | 3401728 |
| 35 | -5251072 |
| 36 | 8105984 |
| 37 | -12513280 |
| 38 | 19316736 |
| 39 | -29818880 |
| 40 | 46030848 |