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) |
|---|---|
| 1 | -1 |
| 2 | 1 |
| 3 | -1 |
| 4 | 3 |
| 5 | -6 |
| 6 | 10 |
| 7 | -15 |
| 8 | 23 |
| 9 | -37 |
| 10 | 61 |
| 11 | -100 |
| 12 | 162 |
| 13 | -261 |
| 14 | 421 |
| 15 | -681 |
| 16 | 1103 |
| 17 | -1786 |
| 18 | 2890 |
| 19 | -4675 |
| 20 | 7563 |
| 21 | -12237 |
| 22 | 19801 |
| 23 | -32040 |
| 24 | 51842 |
| 25 | -83881 |
| 26 | 135721 |
| 27 | -219601 |
| 28 | 355323 |
| 29 | -574926 |
| 30 | 930250 |
| 31 | -1505175 |
| 32 | 2435423 |
| 33 | -3940597 |
| 34 | 6376021 |
| 35 | -10316620 |
| 36 | 16692642 |
| 37 | -27009261 |
| 38 | 43701901 |
| 39 | -70711161 |
| 40 | 114413063 |