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 | 3 |
| 5 | -4 |
| 6 | 6 |
| 7 | -9 |
| 8 | 13 |
| 9 | -19 |
| 10 | 28 |
| 11 | -41 |
| 12 | 60 |
| 13 | -88 |
| 14 | 129 |
| 15 | -189 |
| 16 | 277 |
| 17 | -406 |
| 18 | 595 |
| 19 | -872 |
| 20 | 1278 |
| 21 | -1873 |
| 22 | 2745 |
| 23 | -4023 |
| 24 | 5896 |
| 25 | -8641 |
| 26 | 12664 |
| 27 | -18560 |
| 28 | 27201 |
| 29 | -39865 |
| 30 | 58425 |
| 31 | -85626 |
| 32 | 125491 |
| 33 | -183916 |
| 34 | 269542 |
| 35 | -395033 |
| 36 | 578949 |
| 37 | -848491 |
| 38 | 1243524 |
| 39 | -1822473 |
| 40 | 2670964 |
| 41 | -3914488 |
| 42 | 5736961 |
| 43 | -8407925 |
| 44 | 12322413 |
| 45 | -18059374 |
| 46 | 26467299 |
| 47 | -38789712 |
| 48 | 56849086 |
| 49 | -83316385 |