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 | 2 |
| 4 | -1 |
| 5 | -2 |
| 6 | 6 |
| 7 | -6 |
| 8 | 3 |
| 9 | -1 |
| 10 | -1 |
| 11 | 9 |
| 12 | -18 |
| 13 | 23 |
| 14 | -27 |
| 15 | 23 |
| 16 | -1 |
| 17 | -24 |
| 18 | 49 |
| 19 | -89 |
| 20 | 121 |
| 21 | -117 |
| 22 | 96 |
| 23 | -60 |
| 24 | -18 |
| 25 | 138 |
| 26 | -275 |
| 27 | 408 |
| 28 | -525 |
| 29 | 592 |
| 30 | -566 |
| 31 | 444 |
| 32 | -181 |
| 33 | -276 |
| 34 | 854 |
| 35 | -1485 |
| 36 | 2154 |
| 37 | -2765 |
| 38 | 3157 |
| 39 | -3131 |
| 40 | 2571 |
| 41 | -1468 |
| 42 | -301 |
| 43 | 2813 |
| 44 | -5860 |
| 45 | 9153 |
| 46 | -12386 |
| 47 | 15082 |
| 48 | -16664 |
| 49 | 16558 |
| 50 | -14125 |