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 | 1 |
| 4 | -6 |
| 5 | 1 |
| 6 | -1 |
| 7 | 23 |
| 8 | -23 |
| 9 | 1 |
| 10 | 1 |
| 11 | -76 |
| 12 | 230 |
| 13 | -76 |
| 14 | 1 |
| 15 | -1 |
| 16 | 237 |
| 17 | -1682 |
| 18 | 1682 |
| 19 | -237 |
| 20 | 1 |
| 21 | 1 |
| 22 | -722 |
| 23 | 10543 |
| 24 | -23548 |
| 25 | 10543 |
| 26 | -722 |
| 27 | 1 |
| 28 | -1 |
| 29 | 2179 |
| 30 | -60657 |
| 31 | 259723 |
| 32 | -259723 |
| 33 | 60657 |
| 34 | -2179 |
| 35 | 1 |
| 36 | 1 |
| 37 | -6552 |
| 38 | 331612 |
| 39 | -2485288 |
| 40 | 4675014 |
| 41 | -2485288 |
| 42 | 331612 |
| 43 | -6552 |
| 44 | 1 |
| 45 | -1 |
| 46 | 19673 |
| 47 | -1756340 |
| 48 | 21707972 |
| 49 | -69413294 |
| 50 | 69413294 |
| 51 | -21707972 |
| 52 | 1756340 |
| 53 | -19673 |
| 54 | 1 |