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 | 0 |
| 1 | -1 |
| 2 | 0 |
| 3 | -2 |
| 4 | 1 |
| 5 | -4 |
| 6 | 4 |
| 7 | -9 |
| 8 | 12 |
| 9 | -22 |
| 10 | 33 |
| 11 | -56 |
| 12 | 88 |
| 13 | -145 |
| 14 | 232 |
| 15 | -378 |
| 16 | 609 |
| 17 | -988 |
| 18 | 1596 |
| 19 | -2585 |
| 20 | 4180 |
| 21 | -6766 |
| 22 | 10945 |
| 23 | -17712 |
| 24 | 28656 |
| 25 | -46369 |
| 26 | 75024 |
| 27 | -121394 |
| 28 | 196417 |
| 29 | -317812 |
| 30 | 514228 |
| 31 | -832041 |
| 32 | 1346268 |
| 33 | -2178310 |
| 34 | 3524577 |
| 35 | -5702888 |
| 36 | 9227464 |
| 37 | -14930353 |
| 38 | 24157816 |
| 39 | -39088170 |
| 40 | 63245985 |
| 41 | -102334156 |
| 42 | 165580140 |
| 43 | -267914297 |
| 44 | 433494436 |
| 45 | -701408734 |
| 46 | 1134903169 |
| 47 | -1836311904 |
| 48 | 2971215072 |
| 49 | -4807526977 |
| 50 | 7778742048 |